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Triangle center

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8255: 7846: 3140: 8250:{\displaystyle {\begin{aligned}&{\text{if reference }}\triangle {\text{ is acute:}}\quad \cos A\ :\,\cos B\ :\,\cos C\\&{\begin{array}{rcccc}{\text{if }}\measuredangle A{\text{ is obtuse:}}&\cos A+\sec B\sec C&:&\cos B-\sec B&:&\cos C-\sec C\\{\text{if }}\measuredangle B{\text{ is obtuse:}}&\cos A-\sec A&:&\cos B+\sec C\sec A&:&\cos C-\sec C\\{\text{if }}\measuredangle C{\text{ is obtuse:}}&\cos A-\sec A&:&\cos B-\sec B&:&\cos C+\sec A\sec B\end{array}}\end{aligned}}} 2728: 7456: 7839: 3135:{\displaystyle f(a,b,c)={\begin{cases}1&\quad {\text{if }}a^{2}>b^{2}+bc+c^{2}&\iff {\text{if }}A>2\pi /3\\0&\quad \!\!\displaystyle {{{\text{if }}b^{2}>c^{2}+ca+a^{2}} \atop {{\text{ or }}c^{2}>a^{2}+ab+b^{2}}}&\iff \!\!\displaystyle {{{\text{if }}B>2\pi /3} \atop {{\text{ or }}C>2\pi /3}}\\\csc(A+{\frac {\pi }{3}})&\quad {\text{otherwise }}&\iff A,B,C>2\pi /3\end{cases}}} 40: 7258: 7646: 5104: 4841: 6670:
This is readily seen to be a triangle center function and (provided the triangle is scalene) the corresponding triangle center is the excenter opposite to the largest vertex angle. The other two excenters can be picked out by similar functions. However, as indicated above only one of the excenters of
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Unlike squares and circles, triangles have many centers. The ancient Greeks found four: incenter, centroid, circumcenter, and orthocenter. A fifth center, found much later, is the Fermat point. Thereafter, points now called nine-point center, symmedian point, Gergonne point, and Feuerbach point, to
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The first and second Brocard points are one of many bicentric pairs of points, pairs of points defined from a triangle with the property that the pair (but not each individual point) is preserved under similarities of the triangle. Several binary operations, such as midpoint and trilinear product,
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In the following table of more recent triangle centers, no specific notations are mentioned for the various points. Also for each center only the first trilinear coordinate f(a,b,c) is specified. The other coordinates can be easily derived using the cyclicity property of trilinear coordinates.
7451:{\displaystyle f(a,b,c)={\begin{cases}\alpha &\quad {\text{if }}a<b{\text{ and }}a<c&(a{\text{ is least}}),\\\gamma &\quad {\text{if }}a>b{\text{ and }}a>c&(a{\text{ is greatest}}),\\\beta &\quad {\text{otherwise}}&(a{\text{ is in the middle}}).\end{cases}}} 3149:
is bisymmetric and homogeneous so it is a triangle center function. Moreover, the corresponding triangle center coincides with the obtuse angled vertex whenever any vertex angle exceeds 2π/3, and with the 1st isogonic center otherwise. Therefore, this triangle center is none other than the
6666: 6534: 7834:{\displaystyle f(a,b,c)={\begin{cases}\cos A&{\text{if }}\triangle {\text{ is acute}},\\\cos A+\sec B\sec C&{\text{if }}\measuredangle A{\text{ is obtuse}},\\\cos A-\sec A&{\text{if either}}\measuredangle B{\text{ or }}\measuredangle C{\text{ is obtuse}}.\end{cases}}} 4888: 4625: 2706: 8619:
triangle, bisymmetry ensures that all triangle centers are invariant under reflection. Since rotations and translations may be regarded as double reflections they too must preserve triangle centers. These invariance properties provide justification for the definition.
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This definition ensures that triangle centers of similar triangles meet the invariance criteria specified above. By convention only the first of the three trilinear coordinates of a triangle center is quoted since the other two are obtained by
250:, all triangle centers coincide at its centroid. However the triangle centers generally take different positions from each other on all other triangles. The definitions and properties of thousands of triangle centers have been collected in the 1637: 4582: 1460: 5264: 6551: 7151: 6396: 239:), the center of the transformed triangle is the same point as the transformed center of the original triangle. This invariance is the defining property of a triangle center. It rules out other well-known points such as the 264:
Even though the ancient Greeks discovered the classic centers of a triangle, they had not formulated any definition of a triangle center. After the ancient Greeks, several special points associated with a triangle like the
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under addition, subtraction, and multiplication. This gives an easy way to create new triangle centers. However distinct normalized triangle center functions will often define the same triangle center, for example
6781: 3302: 3236: 2341: 2061: 5099:{\displaystyle {\begin{aligned}\sec(A-{\tfrac {\pi }{3}}):\sec(B-{\tfrac {\pi }{3}}):\sec(C-{\tfrac {\pi }{3}})\\\sec(A+{\tfrac {\pi }{3}}):\sec(B+{\tfrac {\pi }{3}}):\sec(C+{\tfrac {\pi }{3}})\end{aligned}}} 4836:{\displaystyle {\begin{aligned}\sin(A+{\tfrac {\pi }{3}}):\sin(B+{\tfrac {\pi }{3}}):\sin(C+{\tfrac {\pi }{3}})\\\sin(A-{\tfrac {\pi }{3}}):\sin(B-{\tfrac {\pi }{3}}):\sin(C-{\tfrac {\pi }{3}})\end{aligned}}} 3238:
These coordinates satisfy the properties of homogeneity and cyclicity but not bisymmetry. So the first Brocard point is not (in general) a triangle center. The second Brocard point has trilinear coordinates:
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During the revival of interest in triangle geometry in the 1980s it was noticed that these special points share some general properties that now form the basis for a formal definition of triangle center.
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it follows that triangle centers could equally well have been defined in terms of barycentrics instead of trilinears. In practice it isn't difficult to switch from one coordinate system to the other.
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Intersection of the lines connecting each vertex to the center of an equilateral triangle pointed outwards (first Napoleon point) or inwards (second Napoleon point), mounted on the opposite side.
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Routine calculation shows that in every case these trilinears represent the incenter of the tangential triangle. So this point is a triangle center that is a close companion of the circumcenter.
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name a few, were added to the literature. In the 1980s, it was noticed that these special points share some general properties that now form the basis for a formal definition of triangle center
8365: 5560: 3749: 832: 7001: 5929: 1479: 5395: 746: 547: 5846: 7236: 4310: 4186: 1135: 8314: 7492:. Thus every point is potentially a triangle center. However the vast majority of triangle centers are of little interest, just as most continuous functions are of little interest. 1329: 5689: 5476: 3633: 3549: 632: 1045: 6163:
In honor of Clark Kimberling who created the online encyclopedia of more than 32,000 triangle centers, the triangle centers listed in the encyclopedia are collectively called
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is a triangle center function. Since the corresponding triangle center has the same trilinears as the circumcenter, it follows that the circumcenter is a triangle center.
6540:. For an equilateral triangle all three components are equal so all centers coincide with the centroid. So, like a circle, an equilateral triangle has a unique center. 7033: 5329: 4471: 3461: 937: 1806: 3807: 3386: 2714:, one can verify that they indeed satisfy the defining properties of the coordinates of a triangle center. Hence the 1st isogonic center is also a triangle center. 437: 357: 6334: 5135: 410: 330: 377: 6690: 3242: 3176: 3753:
Center of the circle passing through the midpoint of each side, the foot of each altitude, and the midpoint between the orthocenter and each vertex.
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both correspond to the centroid. Two triangle center functions define the same triangle center if and only if their ratio is a function symmetric in
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are both rational and 1 otherwise. Then for any triangle with integer sides the associated triangle center evaluates to 0:0:0 which is undefined.
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Even if a triangle center function is well-defined everywhere the same cannot always be said for its associated triangle center. For example, let
6786: 3843: 6661:{\displaystyle f(a,b,c)={\begin{cases}-1&\quad {\text{if }}a\geq b{\text{ and }}a\geq c,\\\;\;\;1&\quad {\text{otherwise}}.\end{cases}}} 1185: 6536:
so two components of the associated triangle center are always equal. Therefore, all triangle centers of an isosceles triangle must lie on its
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On account of this the definition of triangle center function is sometimes taken to include non-zero homogeneous biantisymmetric functions.
7511: 6529:{\displaystyle {\begin{aligned}f(a,b,c)&=f(b,a,c)&({\text{since }}a=b)\\&=f(b,c,a)&{\text{(by bisymmetry)}}\end{aligned}}} 1969: 1471:
the domain of triangles with an angle exceeding 2π/3 is important; in other words, triangles for which any of the following is true:
2701:{\displaystyle \csc \left(A+{\frac {\pi }{3}}\right):\csc \left(B+{\frac {\pi }{3}}\right):\csc \left(C+{\frac {\pi }{3}}\right).} 8701: 8686:, for instance, can be found for any polygon. Some research has been done on the centers of polygons with more than three sides. 6908: 1057: 295: 252: 5584: 2521:{\displaystyle {\begin{aligned}f(a,c,b)&=a(c^{2}+b^{2}-a^{2})\\&=a(b^{2}+c^{2}-a^{2})\\&=f(a,b,c)\end{aligned}}} 8668:. In non-Euclidean geometry, the assumption that the interior angles of the triangle sum to 180 degrees must be discarded. 7030:. A normalized triangle center function has the same triangle center as the original, and also the stronger property that 7619: 8488: 8374: 4341: 5577: 9289: 8319: 5500: 7916: 3668: 2331:{\displaystyle {\begin{aligned}f(ta,tb,tc)&=ta{\Bigl }\\&=t^{3}{\Bigl }\\&=t^{3}f(a,b,c)\end{aligned}}} 5802: 774: 9305: 8641: 8637: 7682: 7294: 5869: 5353: 656: 9268: 8716: 7634:
There are other center pairs besides the Fermat point and the 1st isogonic center. Another system is formed by
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Intersection of the lines connecting each vertex to the point where the incircle touches the opposite side.
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Intersection of the lines connecting each vertex to the point where an excircle touches the opposite side.
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an isosceles triangle and none of the excenters of an equilateral triangle can ever be a triangle center.
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yet excludes all trivial triangles (i.e. points) and degenerate triangles (i.e. lines) is the set of all
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There are various instances where it may be desirable to restrict the analysis to a smaller domain than
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is the corresponding triangle center whenever the sides of the reference triangle are labelled so that
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Intersection of the symmedians – the reflection of each median about the corresponding angle bisector.
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are concurrent and the point of concurrence is the 1st isogonal center. Its trilinear coordinates are
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cannot be negative. Furthermore, in order to represent the sides of a triangle they must satisfy the
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when applied to the two Brocard points, as well as other bicentric pairs, produce triangle centers.
1632:{\displaystyle a^{2}>b^{2}+bc+c^{2};\quad b^{2}>c^{2}+ca+a^{2};\quad c^{2}>a^{2}+ab+b^{2}.} 8661: 6537: 5706: 3638: 1142: 767:
Every triangle center function corresponds to a unique triangle center. This correspondence is not
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Reflecting a triangle reverses the order of its sides. In the image the coordinates refer to the
4846: 4577:{\displaystyle \csc(A+{\tfrac {\pi }{3}}):\csc(B+{\tfrac {\pi }{3}}):\csc(C+{\tfrac {\pi }{3}}).} 4194: 753: 1261:
is the domain of all triangles, and it is the default domain for all triangle-based functions.
9220: 9163: 9122: 9086: 9076: 8951: 8863: 6114: 5293: 3654: 3466: 3425: 1455:{\displaystyle a^{2}\leq b^{2}+c^{2},\quad b^{2}\leq c^{2}+a^{2},\quad c^{2}\leq a^{2}+b^{2}.} 901: 270: 201: 138: 134: 82: 7641:
and the incenter of the tangential triangle. Consider the triangle center function given by:
5259:{\displaystyle {\frac {bc}{b^{2}-c^{2}}}:{\frac {ca}{c^{2}-a^{2}}}:{\frac {ab}{a^{2}-b^{2}}}} 9278: 9260: 9212: 9155: 9114: 8943: 8834: 8808: 8796: 8768: 8711: 8665: 5862: 4606: 290: 181: 173: 8893: 3780: 3359: 415: 335: 6310: 5346: 4869: 4327: 3766: 3391: 386: 306: 282: 216: 61: 31: 9043: 30:
This article is about a geometry concept. For the place in Lexington, Kentucky, USA, see
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If such a function is also non-zero and homogeneous it is easily seen that the mapping
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be similarly constructed equilateral triangles based on the other two sides of triangle
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which are not invariant under reflection and so fail to qualify as triangle centers.
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Incenter of the medial triangle. Center of mass of a uniform triangular wireframe.
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On the geometry of a triangle in the elliptic and in the extended hyperbolic plane
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Al-Sharif, Abdullah; Hajja, Mowaffaq; Krasopoulos, Panagiotis T. (November 2009).
7146:{\displaystyle f(ta,tb,tc)=f(a,b,c)\quad {\text{for all}}\quad t>0,\ (a,b,c).} 1794:
The point of concurrence of the perpendicular bisectors of the sides of triangle
8672: 4091: 3965: 3574: 223:. In other words, for any triangle and any similarity transformation (such as a 197: 121: 39: 9216: 8799:(11 Apr 2018) . "Central Points and Central Lines in the Plane of a Triangle". 8284:
triangle and (using "|" as the separator) the reflection of an arbitrary point
1957:{\displaystyle a(b^{2}+c^{2}-a^{2}):b(c^{2}+a^{2}-b^{2}):c(a^{2}+b^{2}-c^{2}).} 299:
contains an annotated list of over 50,000 triangle centers. Every entry in the
9264: 9191:"Generalization of Kimberling's Concept of Triangle Center for Other Polygons" 9159: 8721: 7153:
Together with the zero function, normalized triangle center functions form an
6092:{\displaystyle \cos {\tfrac {A}{3}}+2\cos {\tfrac {B}{3}}\cos {\tfrac {C}{3}}} 5780:{\displaystyle \sec {\tfrac {A}{2}}\cos {\tfrac {B}{2}}\cos {\tfrac {C}{2}}-1} 149: 9224: 9190: 9167: 9090: 8955: 7843:
For the corresponding triangle center there are four distinct possibilities:
4190: 768: 3943:{\displaystyle {\frac {bc}{b+c-a}}:{\frac {ca}{c+a-b}}:{\frac {ab}{a+b-c}}} 9070: 8683: 8682:
Some centers can be extended to polygons with more than three sides. The
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be a triangle center function. If two sides of a triangle are equal (say
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Point that is the smallest possible sum of distances from the vertices.
4069:{\displaystyle {\frac {b+c-a}{a}}:{\frac {c+a-b}{b}}:{\frac {a+b-c}{c}}} 8820: 8676: 8371:
is a triangle center function the reflection of its triangle center is
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is the circumcenter. The trilinear coordinates of the circumcenter are
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alone and does not depend on the other angles or on the side lengths.
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has both these properties it is called a triangle center function. If
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that is in some sense in the middle of the triangle. For example, the
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Point in a triangle that can be seen as its middle under some criteria
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actually the 1st isogonic center, but also the Fermat point whenever
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is a triangle center function. The corresponding triangle center is
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Hyperbolic triangle centers : the special relativistic approach
8812: 6776:{\displaystyle f(a,b,c)=-f(a,c,b)\quad {\text{for all}}\quad a,b,c.} 3297:{\displaystyle {\frac {b}{c}}\ :\ {\frac {c}{a}}\ :\ {\frac {a}{b}}} 3231:{\displaystyle {\frac {c}{b}}\ :\ {\frac {a}{c}}\ :\ {\frac {b}{a}}} 9207: 9027: 9021:
Russell, Robert A. (2019-04-18). "Non-Euclidean Triangle Centers".
8660:. Triangle centers that have the same form for both Euclidean and 2056:{\displaystyle f\left(a,b,c\right)=a\left(b^{2}+c^{2}-a^{2}\right)} 9255: 9189:
Prieto-Martínez, Luis Felipe; Sánchez-Cauce, Raquel (2021-04-02).
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has no trilinear representation using only algebraic functions of
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are the side-lengths of a reference triangle then the point whose
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Point at which the nine-point circle is tangent to the incircle.
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The Australian Journal of Mathematical Analysis and Applications
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On Centers and Central Lines of Triangles in the Elliptic Plane
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if the trilinear coordinates of P can be expressed in the form
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can also be defined, by analogy with 2-dimensional triangles.
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The study of triangle centers traditionally is concerned with
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In some cases these functions are not defined on the whole of
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is a viable domain. In order to support the bisymmetry test
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Each of these classical centers has the property that it is
7827: 7444: 6898:{\displaystyle (a,b,c)\to f(a,b,c)^{2}\,f(b,c,a)\,f(c,a,b)} 6654: 3128: 4849:
that transform the triangle into an equilateral triangle.
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The trilinear coordinates of the first Brocard point are:
1248:{\displaystyle a\leq b+c,\quad b\leq c+a,\quad c\leq a+b.} 9110:
Barycentric Calculus in Euclidean and Hyperbolic Geometry
5630:{\displaystyle \tan {\tfrac {A}{2}}+\sec {\tfrac {A}{2}}} 9275:
Triangle Centers in the 2D, 3D, Spherical and Hyperbolic
8920:, Encyclopedia of Triangle Centers, accessed 2012-05-02 379:
is the positional index of the entry. For example, the
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Oakley, Cletus O.; Baker, Justine C. (November 1978).
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A domain of much practical value since it is dense in
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As this is also the triangle center corresponding to
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of a triangle is the second entry and is denoted by
8592:{\displaystyle f(c,b,a)\ |\ f(b,a,c)\ |\ f(a,c,b).} 8478:{\displaystyle f(c,a,b)\ |\ f(b,c,a)\ |\ f(a,b,c),} 5282: 4435:{\displaystyle 1-\cos(B-C):1-\cos(C-A):1-\cos(A-B)} 3320: 8591: 8477: 8359: 8308: 8249: 7833: 7610: 7450: 7230: 7145: 6995: 6897: 6775: 6660: 6528: 6328: 6297: 6137: 6091: 5995: 5923: 5840: 5779: 5683: 5629: 5554: 5470: 5389: 5323: 5258: 5098: 4835: 4576: 4434: 4304: 4180: 4068: 3942: 3801: 3743: 3627: 3543: 3455: 3380: 3296: 3230: 3134: 2700: 2520: 2330: 2055: 1956: 1631: 1464:When differentiating between the Fermat point and 1454: 1247: 1172: 1129: 1039: 995: 962: 931: 883: 826: 740: 626: 541: 431: 404: 371: 351: 324: 9144:"Coincidences of Centers of Plane Quadrilaterals" 2985: 2984: 2866: 2865: 2275: 2223: 2196: 2126: 1654:triangles. It is obtained by removing the planes 8360:{\displaystyle \gamma \ |\ \beta \ |\ \alpha .} 8257:Note that the first is also the circumcenter. 5555:{\displaystyle {\frac {a}{2a^{2}-b^{2}-c^{2}}}} 8839:"This is PART 26: Centers X(50001) – X(52000)" 8656:, but triangle centers can also be studied in 563:Bisymmetry in the second and third variables: 7019:by multiplying it by a symmetric function of 3744:{\displaystyle \cos(B-C):\cos(C-A):\cos(A-B)} 8: 827:{\displaystyle f_{1}(a,b,c)={\tfrac {1}{a}}} 9102: 9100: 6996:{\displaystyle f(a,b,c):f(b,c,a):f(c,a,b).} 5924:{\displaystyle {\frac {a(b+c)^{2}}{b+c-a}}} 7508:and the corresponding triangle center is 6636: 6635: 6634: 5390:{\displaystyle {\frac {1}{\cos B+\cos C}}} 3092: 3088: 2983: 2979: 2829: 2825: 741:{\displaystyle f(a,b,c):f(b,c,a):f(c,a,b)} 9206: 9026: 8554: 8519: 8490: 8440: 8405: 8376: 8343: 8329: 8321: 8289: 8146: 8135: 8038: 8027: 7930: 7919: 7915: 7900: 7884: 7863: 7855: 7850: 7848: 7816: 7805: 7794: 7759: 7748: 7704: 7696: 7677: 7648: 7580: 7549: 7518: 7513: 7504:is a triangle center function then so is 7430: 7417: 7396: 7374: 7360: 7339: 7317: 7303: 7289: 7260: 7216: 7185: 7167: 7098: 7035: 6910: 6870: 6845: 6839: 6788: 6749: 6692: 6643: 6613: 6599: 6582: 6553: 6517: 6464: 6400: 6398: 6312: 6251: 6125: 6123: 6077: 6059: 6035: 6027: 5955: 5895: 5873: 5871: 5826: 5817: 5811: 5759: 5741: 5723: 5715: 5669: 5661: 5615: 5594: 5586: 5543: 5530: 5517: 5504: 5502: 5459: 5446: 5433: 5421: 5357: 5355: 5295: 5247: 5234: 5219: 5207: 5194: 5179: 5167: 5154: 5139: 5137: 5077: 5044: 5011: 4977: 4944: 4911: 4892: 4890: 4814: 4781: 4748: 4714: 4681: 4648: 4629: 4627: 4556: 4523: 4490: 4473: 4343: 4231: 4107: 4042: 4015: 3988: 3986: 3911: 3879: 3847: 3845: 3782: 3670: 3590: 3506: 3427: 3361: 3284: 3265: 3246: 3244: 3218: 3199: 3180: 3178: 3117: 3081: 3065: 3034: 3017: 3016: 3007: 2990: 2989: 2987: 2967: 2945: 2932: 2923: 2922: 2915: 2893: 2880: 2871: 2870: 2868: 2847: 2830: 2817: 2795: 2782: 2773: 2759: 2730: 2710:Expressing these coordinates in terms of 2680: 2645: 2610: 2591: 2471: 2458: 2445: 2416: 2403: 2390: 2345: 2343: 2294: 2274: 2273: 2264: 2251: 2238: 2222: 2221: 2215: 2195: 2194: 2188: 2166: 2144: 2125: 2124: 2074: 2072: 2042: 2029: 2016: 1971: 1942: 1929: 1916: 1894: 1881: 1868: 1846: 1833: 1820: 1808: 1761:. The simplest domain of all is the line 1620: 1598: 1585: 1571: 1549: 1536: 1522: 1500: 1487: 1481: 1443: 1430: 1417: 1403: 1390: 1377: 1363: 1350: 1337: 1331: 1187: 1164: 1160: 1159: 1156: 1117: 1113: 1096: 1092: 1075: 1071: 1065: 1028: 1024: 1023: 1020: 981: 979: 948: 946: 903: 845: 839: 812: 782: 776: 658: 568: 542:{\displaystyle f(ta,tb,tc)=t^{n}f(a,b,c)} 509: 467: 423: 417: 388: 364: 343: 337: 308: 7622:of the triangle center corresponding to 5841:{\displaystyle \sec ^{4}{\tfrac {A}{4}}} 3557:of the sides. Center of the triangle's 2547:be the equilateral triangle having base 8760: 8734: 7231:{\displaystyle (abc)^{-1}(a+b+c)^{3}f.} 4305:{\displaystyle bc(b+c):ca(c+a):ab(a+b)} 4181:{\displaystyle (b+c-a):(c+a-b):(a+b-c)} 1130:{\displaystyle a^{1/2}:b^{1/2}:c^{1/2}} 8309:{\displaystyle \gamma :\beta :\alpha } 4197:(and various equivalent definitions). 9107:Ungar, Abraham Albert (August 2010). 8485:which, by bisymmetry, is the same as 7: 9044:"Hyperbolic Barycentric Coordinates" 5684:{\displaystyle \sec {\tfrac {A}{2}}} 5471:{\displaystyle a(b^{4}+c^{4}-a^{4})} 3628:{\displaystyle \sec A:\sec B:\sec C} 3544:{\displaystyle \cos A:\cos B:\cos C} 1777:which corresponds to the set of all 1145:. So, in practice, every function's 106:(intersect/centered at circumcenter 6375:Isosceles and equilateral triangles 6211:can be expressed as polynomials in 6187:can be expressed as polynomials in 6154:General classes of triangle centers 1717:must be symmetric about the planes 458:may have the following properties: 8648:Non-Euclidean and other geometries 8628:Some other names for dilation are 7860: 7701: 7464:is a triangle center function and 2988: 2869: 645:is a triangle center function and 627:{\displaystyle f(a,b,c)=f(a,c,b).} 25: 8936:The American Mathematical Monthly 7253:be any three real constants. Let 6207:if the trilinear coordinates of 6183:if the trilinear coordinates of 1040:{\displaystyle \mathbb {R} ^{3}.} 43:Five important triangle centers. 9001:MathWorld–A Wolfram Web Resource 8975:MathWorld–A Wolfram Web Resource 8898:MathWorld–A Wolfram Web Resource 8872:MathWorld–A Wolfram Web Resource 8843:Encyclopedia of Triangle Centers 8702:Encyclopedia of Triangle Centers 5268:Various equivalent definitions. 3312:Some well-known triangle centers 1173:{\displaystyle \mathbb {R} ^{3}} 1058:Encyclopedia of Triangle Centers 1056:which is the 365th entry in the 301:Encyclopedia of Triangle Centers 296:Encyclopedia of Triangle Centers 253:Encyclopedia of Triangle Centers 204:, and can be obtained by simple 7868: 7416: 7359: 7302: 7103: 7097: 6754: 6748: 6642: 6598: 3080: 2864: 2772: 1580: 1531: 1412: 1372: 1226: 1207: 1149:is restricted to the region of 1049:For example, the trilinears of 996:{\displaystyle {\tfrac {a}{c}}} 963:{\displaystyle {\tfrac {a}{b}}} 884:{\displaystyle f_{2}(a,b,c)=bc} 8948:10.1080/00029890.1978.11994688 8932:"The Morley Trisector Theorem" 8583: 8565: 8555: 8548: 8530: 8520: 8513: 8495: 8469: 8451: 8441: 8434: 8416: 8406: 8399: 8381: 8344: 8330: 7671: 7653: 7618:Since these are precisely the 7602: 7584: 7571: 7553: 7540: 7522: 7435: 7424: 7401: 7390: 7344: 7333: 7283: 7265: 7213: 7194: 7182: 7169: 7137: 7119: 7094: 7076: 7067: 7040: 6987: 6969: 6960: 6942: 6933: 6915: 6892: 6874: 6867: 6849: 6836: 6817: 6811: 6808: 6790: 6745: 6727: 6715: 6697: 6576: 6558: 6512: 6494: 6478: 6461: 6456: 6438: 6425: 6407: 6356:transcendental triangle center 6346:Transcendental triangle center 6323: 6317: 6298:{\displaystyle f(A):f(B):f(C)} 6292: 6286: 6277: 6271: 6262: 6256: 6138:{\displaystyle {\frac {A}{a}}} 5990: 5963: 5892: 5879: 5465: 5426: 5318: 5300: 5089: 5068: 5056: 5035: 5023: 5002: 4989: 4968: 4956: 4935: 4923: 4902: 4826: 4805: 4793: 4772: 4760: 4739: 4726: 4705: 4693: 4672: 4660: 4639: 4568: 4547: 4535: 4514: 4502: 4481: 4429: 4417: 4399: 4387: 4369: 4357: 4299: 4287: 4275: 4263: 4251: 4239: 4175: 4157: 4151: 4133: 4127: 4109: 3738: 3726: 3714: 3702: 3690: 3678: 3089: 3075: 3056: 2980: 2826: 2753: 2735: 2511: 2493: 2477: 2438: 2422: 2383: 2370: 2352: 2321: 2303: 2270: 2231: 2185: 2175: 2163: 2153: 2141: 2131: 2108: 2081: 1948: 1909: 1900: 1861: 1852: 1813: 926: 908: 869: 851: 806: 788: 735: 717: 708: 690: 681: 663: 618: 600: 591: 573: 536: 518: 499: 472: 399: 393: 319: 313: 1: 7011:Any triangle center function 6230:is the area of the triangle. 748:is called a triangle center. 6118: 6105: 6022: 6009: 5996:{\displaystyle bc(ca+ab-bc)} 5950: 5937: 5866: 5853: 5806: 5793: 5710: 5697: 5656: 5643: 5581: 5578:Congruent isoscelizers point 5568: 5497: 5484: 5416: 5403: 5350: 5337: 3394:. Center of the triangle's 9290:Florida Atlantic University 9286:A Tour of Triangle Geometry 7249:are real variables and let 6338:is a function of the angle 3304:and similar remarks apply. 1316:make specific reference to 760:. This process is known as 9322: 9217:10.1007/s00025-021-01388-4 9069:Ungar, Abraham A. (2010). 9042:Ungar, Abraham A. (2009). 8894:"Triangle Center Function" 6181:polynomial triangle center 6171:Polynomial triangle center 5803:First Ajima-Malfatti point 3317:Classical triangle centers 3166: 221:similarity transformations 48: Reference triangle 29: 9160:10.1007/s00025-009-0417-6 8918:Bicentric Pairs of Points 8264:Bisymmetry and invariance 6675:Biantisymmetric functions 5285: 3323: 9269:University of Evansville 8717:Modern triangle geometry 5947:Equal parallelians point 5653:Yff center of congruence 5324:{\displaystyle f(a,b,c)} 3473:of a uniform triangular 3456:{\displaystyle bc:ca:ab} 2555:on the negative side of 2338:as well as bisymmetric: 1320:, namely that region of 932:{\displaystyle f(a,b,c)} 454:of three real variables 18:Triangle center function 9075:. Dordrecht: Springer. 8997:"Major Triangle Center" 8664:can be expressed using 8624:Alternative terminology 7620:barycentric coordinates 7496:Barycentric coordinates 6195:Regular triangle center 5275:Recent triangle centers 3555:perpendicular bisectors 100:Perpendicular bisectors 68:(intersect/centered at 9195:Results in Mathematics 9148:Results in Mathematics 8675:or higher-dimensional 8658:non-Euclidean geometry 8593: 8479: 8361: 8310: 8251: 7835: 7612: 7452: 7432: is in the middle 7232: 7147: 6997: 6899: 6777: 6662: 6530: 6330: 6299: 6205:regular triangle point 6139: 6093: 5997: 5925: 5842: 5781: 5685: 5631: 5556: 5472: 5391: 5325: 5260: 5100: 4837: 4578: 4436: 4306: 4182: 4070: 3944: 3803: 3745: 3629: 3545: 3457: 3382: 3329:Trilinear coordinates 3298: 3232: 3136: 2702: 2522: 2332: 2057: 1958: 1633: 1456: 1249: 1174: 1131: 1041: 997: 964: 933: 885: 828: 742: 628: 543: 433: 406: 373: 353: 326: 157: 8594: 8480: 8362: 8311: 8252: 7836: 7613: 7453: 7241:Uninteresting centers 7233: 7148: 6998: 6900: 6778: 6663: 6531: 6331: 6300: 6244:major triangle center 6234:Major triangle center 6140: 6115:Hofstadter zero point 6094: 5998: 5926: 5843: 5782: 5686: 5632: 5557: 5473: 5392: 5326: 5261: 5101: 4838: 4579: 4437: 4307: 4183: 4071: 3945: 3804: 3802:{\displaystyle a:b:c} 3746: 3630: 3546: 3458: 3383: 3381:{\displaystyle 1:1:1} 3299: 3233: 3137: 2703: 2523: 2333: 2063:It can be shown that 2058: 1959: 1779:equilateral triangles 1634: 1457: 1250: 1175: 1132: 1042: 998: 965: 934: 886: 829: 743: 651:trilinear coordinates 629: 544: 434: 432:{\displaystyle X_{2}} 407: 374: 354: 352:{\displaystyle X_{n}} 327: 200:were familiar to the 42: 9113:. WORLD SCIENTIFIC. 8801:Mathematics Magazine 8489: 8375: 8320: 8288: 7847: 7647: 7512: 7259: 7166: 7034: 7007:New centers from old 6909: 6787: 6691: 6552: 6397: 6329:{\displaystyle f(X)} 6311: 6250: 6122: 6026: 5954: 5870: 5810: 5714: 5660: 5585: 5501: 5420: 5354: 5294: 5286:ETC reference; Name 5136: 4889: 4626: 4472: 4342: 4230: 4106: 3985: 3844: 3781: 3669: 3637:Intersection of the 3589: 3559:circumscribed circle 3553:Intersection of the 3505: 3465:Intersection of the 3426: 3390:Intersection of the 3360: 3243: 3177: 2729: 2590: 2342: 2071: 1970: 1807: 1480: 1330: 1265:Other useful domains 1186: 1155: 1064: 1019: 978: 945: 902: 838: 775: 657: 567: 466: 449:real-valued function 416: 405:{\displaystyle X(2)} 387: 363: 336: 325:{\displaystyle X(n)} 307: 248:equilateral triangle 8995:Weisstein, Eric W. 8971:"Kimberling Center" 8969:Weisstein, Eric W. 8892:Weisstein, Eric W. 8662:hyperbolic geometry 6350:A triangle center 6199:A triangle center 6175:A triangle center 5707:Isoperimetric point 2536:1st isogonic center 1143:triangle inequality 8773:"Triangle centers" 8654:Euclidean geometry 8589: 8475: 8357: 8306: 8247: 8245: 8241: 7857:if reference  7831: 7826: 7608: 7448: 7443: 7228: 7143: 6993: 6895: 6773: 6658: 6653: 6526: 6524: 6326: 6295: 6238:A triangle center 6165:Kimberling centers 6135: 6089: 6087: 6069: 6045: 5993: 5921: 5838: 5836: 5777: 5769: 5751: 5733: 5681: 5679: 5627: 5625: 5604: 5552: 5468: 5387: 5321: 5256: 5096: 5094: 5087: 5054: 5021: 4987: 4954: 4921: 4833: 4831: 4824: 4791: 4758: 4724: 4691: 4658: 4574: 4566: 4533: 4500: 4432: 4302: 4195:excentral triangle 4178: 4066: 3940: 3799: 3741: 3625: 3541: 3453: 3378: 3294: 3228: 3132: 3127: 3045: 2976: 2698: 2518: 2516: 2328: 2326: 2053: 1954: 1629: 1452: 1245: 1170: 1127: 1037: 993: 991: 960: 958: 929: 881: 824: 822: 754:cyclic permutation 738: 624: 549:for some constant 539: 429: 402: 369: 349: 322: 158: 144:which, along with 9128:978-981-4304-93-1 9082:978-90-481-8637-2 8868:"Triangle Center" 8864:Weisstein, Eric W 8835:Kimberling, Clark 8797:Kimberling, Clark 8769:Kimberling, Clark 8634:isotropic scaling 8561: 8553: 8526: 8518: 8447: 8439: 8412: 8404: 8350: 8342: 8336: 8328: 8149: 8138: 8041: 8030: 7933: 7922: 7896: 7880: 7866: 7858: 7819: 7808: 7797: 7762: 7751: 7707: 7699: 7433: 7420: 7399: 7398: is greatest 7377: 7363: 7342: 7320: 7306: 7118: 7101: 6752: 6646: 6616: 6602: 6520: 6467: 6159:Kimberling center 6151: 6150: 6133: 6086: 6068: 6044: 5919: 5835: 5768: 5750: 5732: 5678: 5624: 5603: 5550: 5385: 5272: 5271: 5254: 5214: 5174: 5086: 5053: 5020: 4986: 4953: 4920: 4823: 4790: 4757: 4723: 4690: 4657: 4607:Isodynamic points 4565: 4532: 4499: 4064: 4037: 4010: 3938: 3906: 3874: 3655:Nine-point center 3292: 3283: 3277: 3273: 3264: 3258: 3254: 3226: 3217: 3211: 3207: 3198: 3192: 3188: 3084: 3073: 3043: 3020: 2993: 2974: 2926: 2874: 2833: 2776: 2688: 2653: 2618: 2580:. Then the lines 1701:Not every subset 990: 957: 821: 443:Formal definition 372:{\displaystyle n} 285:were discovered. 271:nine-point center 139:nine-point center 135:Nine-point circle 16:(Redirected from 9313: 9306:Triangle centers 9279:Wolfram Research 9265:Triangle Centers 9261:Clark Kimberling 9237: 9236: 9210: 9186: 9180: 9179: 9154:(3–4): 231–247. 9139: 9133: 9132: 9104: 9095: 9094: 9066: 9060: 9058: 9048: 9039: 9033: 9032: 9030: 9018: 9012: 9011: 9009: 9007: 8992: 8986: 8985: 8983: 8981: 8966: 8960: 8959: 8927: 8921: 8915: 8909: 8908: 8906: 8904: 8889: 8883: 8882: 8880: 8878: 8860: 8854: 8853: 8851: 8849: 8831: 8825: 8824: 8793: 8787: 8786: 8780: 8779: 8765: 8754: 8739: 8712:Central triangle 8666:gyrotrigonometry 8618: 8603:relative to the 8602: 8598: 8596: 8595: 8590: 8559: 8558: 8551: 8524: 8523: 8516: 8484: 8482: 8481: 8476: 8445: 8444: 8437: 8410: 8409: 8402: 8370: 8366: 8364: 8363: 8358: 8348: 8347: 8340: 8334: 8333: 8326: 8315: 8313: 8312: 8307: 8283: 8256: 8254: 8253: 8248: 8246: 8242: 8150: 8148: is obtuse: 8147: 8139: 8136: 8042: 8040: is obtuse: 8039: 8031: 8028: 7934: 7932: is obtuse: 7931: 7923: 7920: 7913: 7894: 7878: 7867: 7864: 7859: 7856: 7853: 7840: 7838: 7837: 7832: 7830: 7829: 7820: 7817: 7809: 7806: 7798: 7795: 7763: 7760: 7752: 7749: 7708: 7705: 7700: 7697: 7625: 7617: 7615: 7614: 7609: 7507: 7503: 7491: 7477: 7463: 7457: 7455: 7454: 7449: 7447: 7446: 7434: 7431: 7421: 7418: 7400: 7397: 7378: 7375: 7364: 7361: 7343: 7340: 7321: 7318: 7307: 7304: 7252: 7248: 7237: 7235: 7234: 7229: 7221: 7220: 7193: 7192: 7161: 7152: 7150: 7149: 7144: 7116: 7102: 7099: 7029: 7022: 7014: 7002: 7000: 6999: 6994: 6904: 6902: 6901: 6896: 6844: 6843: 6782: 6780: 6779: 6774: 6753: 6750: 6682: 6667: 6665: 6664: 6659: 6657: 6656: 6647: 6644: 6617: 6614: 6603: 6600: 6538:line of symmetry 6535: 6533: 6532: 6527: 6525: 6521: 6518: 6484: 6468: 6465: 6392: 6382: 6365: 6361: 6353: 6341: 6337: 6335: 6333: 6332: 6327: 6304: 6302: 6301: 6296: 6242:is said to be a 6241: 6229: 6225: 6210: 6202: 6190: 6186: 6178: 6144: 6142: 6141: 6136: 6134: 6126: 6098: 6096: 6095: 6090: 6088: 6079: 6070: 6061: 6046: 6037: 6002: 6000: 5999: 5994: 5930: 5928: 5927: 5922: 5920: 5918: 5901: 5900: 5899: 5874: 5863:Apollonius point 5847: 5845: 5844: 5839: 5837: 5828: 5822: 5821: 5786: 5784: 5783: 5778: 5770: 5761: 5752: 5743: 5734: 5725: 5690: 5688: 5687: 5682: 5680: 5671: 5636: 5634: 5633: 5628: 5626: 5617: 5605: 5596: 5561: 5559: 5558: 5553: 5551: 5549: 5548: 5547: 5535: 5534: 5522: 5521: 5505: 5477: 5475: 5474: 5469: 5464: 5463: 5451: 5450: 5438: 5437: 5396: 5394: 5393: 5388: 5386: 5384: 5358: 5330: 5328: 5327: 5322: 5283: 5265: 5263: 5262: 5257: 5255: 5253: 5252: 5251: 5239: 5238: 5228: 5220: 5215: 5213: 5212: 5211: 5199: 5198: 5188: 5180: 5175: 5173: 5172: 5171: 5159: 5158: 5148: 5140: 5130: 5105: 5103: 5102: 5097: 5095: 5088: 5079: 5055: 5046: 5022: 5013: 4988: 4979: 4955: 4946: 4922: 4913: 4883: 4842: 4840: 4839: 4834: 4832: 4825: 4816: 4792: 4783: 4759: 4750: 4725: 4716: 4692: 4683: 4659: 4650: 4620: 4583: 4581: 4580: 4575: 4567: 4558: 4534: 4525: 4501: 4492: 4466: 4441: 4439: 4438: 4433: 4336: 4311: 4309: 4308: 4303: 4224: 4187: 4185: 4184: 4179: 4100: 4075: 4073: 4072: 4067: 4065: 4060: 4043: 4038: 4033: 4016: 4011: 4006: 3989: 3979: 3949: 3947: 3946: 3941: 3939: 3937: 3920: 3912: 3907: 3905: 3888: 3880: 3875: 3873: 3856: 3848: 3838: 3808: 3806: 3805: 3800: 3775: 3750: 3748: 3747: 3742: 3663: 3634: 3632: 3631: 3626: 3583: 3550: 3548: 3547: 3542: 3499: 3462: 3460: 3459: 3454: 3420: 3396:inscribed circle 3387: 3385: 3384: 3379: 3354: 3321: 3303: 3301: 3300: 3295: 3293: 3285: 3281: 3275: 3274: 3266: 3262: 3256: 3255: 3247: 3237: 3235: 3234: 3229: 3227: 3219: 3215: 3209: 3208: 3200: 3196: 3190: 3189: 3181: 3148: 3141: 3139: 3138: 3133: 3131: 3130: 3121: 3085: 3082: 3074: 3066: 3044: 3042: 3038: 3021: 3018: 3015: 3011: 2994: 2991: 2975: 2973: 2972: 2971: 2950: 2949: 2937: 2936: 2927: 2924: 2921: 2920: 2919: 2898: 2897: 2885: 2884: 2875: 2872: 2851: 2834: 2831: 2822: 2821: 2800: 2799: 2787: 2786: 2777: 2774: 2713: 2707: 2705: 2704: 2699: 2694: 2690: 2689: 2681: 2659: 2655: 2654: 2646: 2624: 2620: 2619: 2611: 2583: 2579: 2572: 2565: 2558: 2554: 2550: 2546: 2531: 2527: 2525: 2524: 2519: 2517: 2483: 2476: 2475: 2463: 2462: 2450: 2449: 2428: 2421: 2420: 2408: 2407: 2395: 2394: 2337: 2335: 2334: 2329: 2327: 2299: 2298: 2283: 2279: 2278: 2269: 2268: 2256: 2255: 2243: 2242: 2227: 2226: 2220: 2219: 2204: 2200: 2199: 2193: 2192: 2171: 2170: 2149: 2148: 2130: 2129: 2067:is homogeneous: 2066: 2062: 2060: 2059: 2054: 2052: 2048: 2047: 2046: 2034: 2033: 2021: 2020: 2000: 1996: 1963: 1961: 1960: 1955: 1947: 1946: 1934: 1933: 1921: 1920: 1899: 1898: 1886: 1885: 1873: 1872: 1851: 1850: 1838: 1837: 1825: 1824: 1800: 1776: 1760: 1746: 1736: 1726: 1716: 1710: 1689: 1683: 1673: 1663: 1649: 1638: 1636: 1635: 1630: 1625: 1624: 1603: 1602: 1590: 1589: 1576: 1575: 1554: 1553: 1541: 1540: 1527: 1526: 1505: 1504: 1492: 1491: 1461: 1459: 1458: 1453: 1448: 1447: 1435: 1434: 1422: 1421: 1408: 1407: 1395: 1394: 1382: 1381: 1368: 1367: 1355: 1354: 1342: 1341: 1325: 1274: 1260: 1254: 1252: 1251: 1246: 1181: 1179: 1177: 1176: 1171: 1169: 1168: 1163: 1140: 1136: 1134: 1133: 1128: 1126: 1125: 1121: 1105: 1104: 1100: 1084: 1083: 1079: 1048: 1046: 1044: 1043: 1038: 1033: 1032: 1027: 1004: 1002: 1000: 999: 994: 992: 983: 971: 969: 967: 966: 961: 959: 950: 938: 936: 935: 930: 894: 890: 888: 887: 882: 850: 849: 833: 831: 830: 825: 823: 814: 787: 786: 759: 747: 745: 744: 739: 648: 644: 640: 633: 631: 630: 625: 559: 552: 548: 546: 545: 540: 514: 513: 457: 453: 438: 436: 435: 430: 428: 427: 411: 409: 408: 403: 378: 376: 375: 370: 358: 356: 355: 350: 348: 347: 331: 329: 328: 323: 291:Clark Kimberling 215:(more precisely 154: 147: 143: 132: 126: 115: 109: 97: 91: 80: 74: 59: 54: 47: 21: 9321: 9320: 9316: 9315: 9314: 9312: 9311: 9310: 9296: 9295: 9254:Manfred Evers, 9248:Manfred Evers, 9245: 9240: 9188: 9187: 9183: 9141: 9140: 9136: 9129: 9106: 9105: 9098: 9083: 9068: 9067: 9063: 9046: 9041: 9040: 9036: 9020: 9019: 9015: 9005: 9003: 8994: 8993: 8989: 8979: 8977: 8968: 8967: 8963: 8929: 8928: 8924: 8916: 8912: 8902: 8900: 8891: 8890: 8886: 8876: 8874: 8862: 8861: 8857: 8847: 8845: 8833: 8832: 8828: 8813:10.2307/2690608 8795: 8794: 8790: 8777: 8775: 8767: 8766: 8762: 8758: 8757: 8740: 8736: 8731: 8726: 8692: 8650: 8630:uniform scaling 8626: 8604: 8600: 8487: 8486: 8373: 8372: 8368: 8318: 8317: 8286: 8285: 8269: 8266: 8244: 8243: 8240: 8239: 8207: 8202: 8179: 8174: 8151: 8132: 8131: 8108: 8103: 8071: 8066: 8043: 8024: 8023: 8000: 7995: 7972: 7967: 7935: 7911: 7910: 7865: is acute: 7845: 7844: 7825: 7824: 7818: is obtuse 7792: 7768: 7767: 7761: is obtuse 7746: 7713: 7712: 7694: 7678: 7645: 7644: 7640: 7632: 7623: 7510: 7509: 7505: 7501: 7498: 7479: 7465: 7461: 7442: 7441: 7422: 7414: 7408: 7407: 7388: 7376: and  7357: 7351: 7350: 7331: 7319: and  7300: 7290: 7257: 7256: 7250: 7246: 7243: 7212: 7181: 7164: 7163: 7159: 7032: 7031: 7024: 7020: 7012: 7009: 6907: 6906: 6835: 6785: 6784: 6689: 6688: 6685:biantisymmetric 6680: 6677: 6652: 6651: 6640: 6631: 6630: 6615: and  6596: 6583: 6550: 6549: 6546: 6523: 6522: 6519:(by bisymmetry) 6515: 6482: 6481: 6459: 6428: 6395: 6394: 6384: 6380: 6377: 6372: 6363: 6359: 6351: 6348: 6339: 6309: 6308: 6306: 6248: 6247: 6239: 6236: 6227: 6212: 6208: 6200: 6197: 6188: 6184: 6176: 6173: 6161: 6156: 6120: 6119: 6111: 6024: 6023: 6015: 5952: 5951: 5943: 5902: 5891: 5875: 5868: 5867: 5859: 5813: 5808: 5807: 5799: 5712: 5711: 5703: 5658: 5657: 5649: 5583: 5582: 5574: 5539: 5526: 5513: 5509: 5499: 5498: 5490: 5455: 5442: 5429: 5418: 5417: 5409: 5362: 5352: 5351: 5347:Schiffler point 5343: 5333:Year described 5292: 5291: 5290: 5289:Center function 5277: 5243: 5230: 5229: 5221: 5203: 5190: 5189: 5181: 5163: 5150: 5149: 5141: 5134: 5133: 5126: 5118: 5093: 5092: 4993: 4992: 4887: 4886: 4878: 4874: 4870:Napoleon points 4866: 4860: 4859: 4830: 4829: 4730: 4729: 4624: 4623: 4615: 4611: 4603: 4597: 4596: 4470: 4469: 4462: 4454: 4340: 4339: 4332: 4328:Feuerbach point 4324: 4228: 4227: 4223: 4215: 4207: 4104: 4103: 4096: 4088: 4044: 4017: 3990: 3983: 3982: 3978: 3970: 3962: 3921: 3913: 3889: 3881: 3857: 3849: 3842: 3841: 3837: 3829: 3821: 3779: 3778: 3771: 3767:Symmedian point 3763: 3667: 3666: 3659: 3651: 3587: 3586: 3579: 3571: 3503: 3502: 3495: 3487: 3424: 3423: 3416: 3408: 3392:angle bisectors 3358: 3357: 3350: 3342: 3325: 3324:ETC reference; 3319: 3314: 3241: 3240: 3175: 3174: 3171: 3165: 3160: 3146: 3126: 3125: 3086: 3083:otherwise  3078: 3047: 3046: 2977: 2963: 2941: 2928: 2911: 2889: 2876: 2862: 2856: 2855: 2823: 2813: 2791: 2778: 2770: 2760: 2727: 2726: 2720: 2711: 2673: 2669: 2638: 2634: 2603: 2599: 2588: 2587: 2581: 2574: 2567: 2560: 2556: 2552: 2548: 2541: 2538: 2529: 2515: 2514: 2481: 2480: 2467: 2454: 2441: 2426: 2425: 2412: 2399: 2386: 2373: 2340: 2339: 2325: 2324: 2290: 2281: 2280: 2260: 2247: 2234: 2211: 2202: 2201: 2184: 2162: 2140: 2111: 2069: 2068: 2064: 2038: 2025: 2012: 2011: 2007: 1980: 1976: 1968: 1967: 1938: 1925: 1912: 1890: 1877: 1864: 1842: 1829: 1816: 1805: 1804: 1795: 1792: 1787: 1762: 1748: 1738: 1728: 1718: 1712: 1702: 1699: 1697:Domain symmetry 1685: 1675: 1665: 1655: 1645: 1616: 1594: 1581: 1567: 1545: 1532: 1518: 1496: 1483: 1478: 1477: 1470: 1439: 1426: 1413: 1399: 1386: 1373: 1359: 1346: 1333: 1328: 1327: 1321: 1318:acute triangles 1315: 1308: 1301: 1294: 1287: 1275:. For example: 1270: 1267: 1256: 1184: 1183: 1158: 1153: 1152: 1150: 1138: 1109: 1088: 1067: 1062: 1061: 1055: 1022: 1017: 1016: 1014: 1011: 976: 975: 973: 943: 942: 940: 900: 899: 892: 841: 836: 835: 778: 773: 772: 757: 655: 654: 646: 642: 638: 565: 564: 554: 550: 505: 464: 463: 455: 451: 445: 419: 414: 413: 385: 384: 361: 360: 339: 334: 333: 305: 304: 283:Feuerbach point 262: 170:triangle centre 166:triangle center 156: 152: 145: 141: 130: 128: 124: 113: 111: 107: 95: 93: 89: 78: 76: 72: 62:Angle bisectors 57: 55: 49: 45: 35: 32:Triangle Center 28: 23: 22: 15: 12: 11: 5: 9319: 9317: 9309: 9308: 9298: 9297: 9294: 9293: 9282: 9271: 9258: 9252: 9244: 9243:External links 9241: 9239: 9238: 9181: 9134: 9127: 9096: 9081: 9061: 9034: 9013: 8987: 8961: 8942:(9): 737–745. 8922: 8910: 8884: 8855: 8826: 8807:(3): 163–187. 8788: 8759: 8756: 8755: 8733: 8732: 8730: 8727: 8725: 8724: 8719: 8714: 8709: 8707:Triangle conic 8704: 8699: 8693: 8691: 8688: 8649: 8646: 8625: 8622: 8588: 8585: 8582: 8579: 8576: 8573: 8570: 8567: 8564: 8557: 8550: 8547: 8544: 8541: 8538: 8535: 8532: 8529: 8522: 8515: 8512: 8509: 8506: 8503: 8500: 8497: 8494: 8474: 8471: 8468: 8465: 8462: 8459: 8456: 8453: 8450: 8443: 8436: 8433: 8430: 8427: 8424: 8421: 8418: 8415: 8408: 8401: 8398: 8395: 8392: 8389: 8386: 8383: 8380: 8356: 8353: 8346: 8339: 8332: 8325: 8305: 8302: 8299: 8296: 8293: 8265: 8262: 8238: 8235: 8232: 8229: 8226: 8223: 8220: 8217: 8214: 8211: 8208: 8206: 8203: 8201: 8198: 8195: 8192: 8189: 8186: 8183: 8180: 8178: 8175: 8173: 8170: 8167: 8164: 8161: 8158: 8155: 8152: 8145: 8142: 8134: 8133: 8130: 8127: 8124: 8121: 8118: 8115: 8112: 8109: 8107: 8104: 8102: 8099: 8096: 8093: 8090: 8087: 8084: 8081: 8078: 8075: 8072: 8070: 8067: 8065: 8062: 8059: 8056: 8053: 8050: 8047: 8044: 8037: 8034: 8026: 8025: 8022: 8019: 8016: 8013: 8010: 8007: 8004: 8001: 7999: 7996: 7994: 7991: 7988: 7985: 7982: 7979: 7976: 7973: 7971: 7968: 7966: 7963: 7960: 7957: 7954: 7951: 7948: 7945: 7942: 7939: 7936: 7929: 7926: 7918: 7917: 7914: 7912: 7909: 7906: 7903: 7899: 7893: 7890: 7887: 7883: 7877: 7874: 7871: 7862: 7854: 7852: 7828: 7823: 7815: 7812: 7807: or  7804: 7801: 7793: 7791: 7788: 7785: 7782: 7779: 7776: 7773: 7770: 7769: 7766: 7758: 7755: 7747: 7745: 7742: 7739: 7736: 7733: 7730: 7727: 7724: 7721: 7718: 7715: 7714: 7711: 7706: is acute 7703: 7695: 7693: 7690: 7687: 7684: 7683: 7681: 7676: 7673: 7670: 7667: 7664: 7661: 7658: 7655: 7652: 7638: 7631: 7630:Binary systems 7628: 7607: 7604: 7601: 7598: 7595: 7592: 7589: 7586: 7583: 7579: 7576: 7573: 7570: 7567: 7564: 7561: 7558: 7555: 7552: 7548: 7545: 7542: 7539: 7536: 7533: 7530: 7527: 7524: 7521: 7517: 7497: 7494: 7445: 7440: 7437: 7429: 7426: 7423: 7415: 7413: 7410: 7409: 7406: 7403: 7395: 7392: 7389: 7387: 7384: 7381: 7373: 7370: 7367: 7358: 7356: 7353: 7352: 7349: 7346: 7341: is least 7338: 7335: 7332: 7330: 7327: 7324: 7316: 7313: 7310: 7301: 7299: 7296: 7295: 7293: 7288: 7285: 7282: 7279: 7276: 7273: 7270: 7267: 7264: 7242: 7239: 7227: 7224: 7219: 7215: 7211: 7208: 7205: 7202: 7199: 7196: 7191: 7188: 7184: 7180: 7177: 7174: 7171: 7142: 7139: 7136: 7133: 7130: 7127: 7124: 7121: 7115: 7112: 7109: 7106: 7096: 7093: 7090: 7087: 7084: 7081: 7078: 7075: 7072: 7069: 7066: 7063: 7060: 7057: 7054: 7051: 7048: 7045: 7042: 7039: 7008: 7005: 6992: 6989: 6986: 6983: 6980: 6977: 6974: 6971: 6968: 6965: 6962: 6959: 6956: 6953: 6950: 6947: 6944: 6941: 6938: 6935: 6932: 6929: 6926: 6923: 6920: 6917: 6914: 6894: 6891: 6888: 6885: 6882: 6879: 6876: 6873: 6869: 6866: 6863: 6860: 6857: 6854: 6851: 6848: 6842: 6838: 6834: 6831: 6828: 6825: 6822: 6819: 6816: 6813: 6810: 6807: 6804: 6801: 6798: 6795: 6792: 6772: 6769: 6766: 6763: 6760: 6757: 6747: 6744: 6741: 6738: 6735: 6732: 6729: 6726: 6723: 6720: 6717: 6714: 6711: 6708: 6705: 6702: 6699: 6696: 6676: 6673: 6655: 6650: 6641: 6639: 6633: 6632: 6629: 6626: 6623: 6620: 6612: 6609: 6606: 6597: 6595: 6592: 6589: 6588: 6586: 6581: 6578: 6575: 6572: 6569: 6566: 6563: 6560: 6557: 6545: 6542: 6516: 6514: 6511: 6508: 6505: 6502: 6499: 6496: 6493: 6490: 6487: 6485: 6483: 6480: 6477: 6474: 6471: 6463: 6460: 6458: 6455: 6452: 6449: 6446: 6443: 6440: 6437: 6434: 6431: 6429: 6427: 6424: 6421: 6418: 6415: 6412: 6409: 6406: 6403: 6402: 6376: 6373: 6371: 6368: 6347: 6344: 6325: 6322: 6319: 6316: 6294: 6291: 6288: 6285: 6282: 6279: 6276: 6273: 6270: 6267: 6264: 6261: 6258: 6255: 6235: 6232: 6196: 6193: 6172: 6169: 6160: 6157: 6155: 6152: 6149: 6148: 6145: 6132: 6129: 6117: 6112: 6109: 6103: 6102: 6099: 6085: 6082: 6076: 6073: 6067: 6064: 6058: 6055: 6052: 6049: 6043: 6040: 6034: 6031: 6021: 6016: 6013: 6007: 6006: 6003: 5992: 5989: 5986: 5983: 5980: 5977: 5974: 5971: 5968: 5965: 5962: 5959: 5949: 5944: 5941: 5935: 5934: 5931: 5917: 5914: 5911: 5908: 5905: 5898: 5894: 5890: 5887: 5884: 5881: 5878: 5865: 5860: 5857: 5851: 5850: 5848: 5834: 5831: 5825: 5820: 5816: 5805: 5800: 5797: 5791: 5790: 5787: 5776: 5773: 5767: 5764: 5758: 5755: 5749: 5746: 5740: 5737: 5731: 5728: 5722: 5719: 5709: 5704: 5701: 5695: 5694: 5691: 5677: 5674: 5668: 5665: 5655: 5650: 5647: 5641: 5640: 5637: 5623: 5620: 5614: 5611: 5608: 5602: 5599: 5593: 5590: 5580: 5575: 5572: 5566: 5565: 5562: 5546: 5542: 5538: 5533: 5529: 5525: 5520: 5516: 5512: 5508: 5496: 5491: 5488: 5482: 5481: 5478: 5467: 5462: 5458: 5454: 5449: 5445: 5441: 5436: 5432: 5428: 5425: 5415: 5410: 5407: 5401: 5400: 5397: 5383: 5380: 5377: 5374: 5371: 5368: 5365: 5361: 5349: 5344: 5341: 5335: 5334: 5331: 5320: 5317: 5314: 5311: 5308: 5305: 5302: 5299: 5287: 5276: 5273: 5270: 5269: 5266: 5250: 5246: 5242: 5237: 5233: 5227: 5224: 5218: 5210: 5206: 5202: 5197: 5193: 5187: 5184: 5178: 5170: 5166: 5162: 5157: 5153: 5147: 5144: 5131: 5124: 5119: 5116: 5110: 5109: 5106: 5091: 5085: 5082: 5076: 5073: 5070: 5067: 5064: 5061: 5058: 5052: 5049: 5043: 5040: 5037: 5034: 5031: 5028: 5025: 5019: 5016: 5010: 5007: 5004: 5001: 4998: 4995: 4994: 4991: 4985: 4982: 4976: 4973: 4970: 4967: 4964: 4961: 4958: 4952: 4949: 4943: 4940: 4937: 4934: 4931: 4928: 4925: 4919: 4916: 4910: 4907: 4904: 4901: 4898: 4895: 4894: 4884: 4872: 4867: 4864: 4857: 4851: 4850: 4843: 4828: 4822: 4819: 4813: 4810: 4807: 4804: 4801: 4798: 4795: 4789: 4786: 4780: 4777: 4774: 4771: 4768: 4765: 4762: 4756: 4753: 4747: 4744: 4741: 4738: 4735: 4732: 4731: 4728: 4722: 4719: 4713: 4710: 4707: 4704: 4701: 4698: 4695: 4689: 4686: 4680: 4677: 4674: 4671: 4668: 4665: 4662: 4656: 4653: 4647: 4644: 4641: 4638: 4635: 4632: 4631: 4621: 4609: 4604: 4601: 4594: 4588: 4587: 4584: 4573: 4570: 4564: 4561: 4555: 4552: 4549: 4546: 4543: 4540: 4537: 4531: 4528: 4522: 4519: 4516: 4513: 4510: 4507: 4504: 4498: 4495: 4489: 4486: 4483: 4480: 4477: 4467: 4460: 4455: 4452: 4446: 4445: 4442: 4431: 4428: 4425: 4422: 4419: 4416: 4413: 4410: 4407: 4404: 4401: 4398: 4395: 4392: 4389: 4386: 4383: 4380: 4377: 4374: 4371: 4368: 4365: 4362: 4359: 4356: 4353: 4350: 4347: 4337: 4330: 4325: 4322: 4316: 4315: 4312: 4301: 4298: 4295: 4292: 4289: 4286: 4283: 4280: 4277: 4274: 4271: 4268: 4265: 4262: 4259: 4256: 4253: 4250: 4247: 4244: 4241: 4238: 4235: 4225: 4219: 4213: 4211:Spieker center 4208: 4205: 4199: 4198: 4188: 4177: 4174: 4171: 4168: 4165: 4162: 4159: 4156: 4153: 4150: 4147: 4144: 4141: 4138: 4135: 4132: 4129: 4126: 4123: 4120: 4117: 4114: 4111: 4101: 4094: 4089: 4086: 4080: 4079: 4076: 4063: 4059: 4056: 4053: 4050: 4047: 4041: 4036: 4032: 4029: 4026: 4023: 4020: 4014: 4009: 4005: 4002: 3999: 3996: 3993: 3980: 3974: 3968: 3963: 3960: 3954: 3953: 3950: 3936: 3933: 3930: 3927: 3924: 3919: 3916: 3910: 3904: 3901: 3898: 3895: 3892: 3887: 3884: 3878: 3872: 3869: 3866: 3863: 3860: 3855: 3852: 3839: 3833: 3827: 3825:Gergonne point 3822: 3819: 3813: 3812: 3809: 3798: 3795: 3792: 3789: 3786: 3776: 3769: 3764: 3761: 3755: 3754: 3751: 3740: 3737: 3734: 3731: 3728: 3725: 3722: 3719: 3716: 3713: 3710: 3707: 3704: 3701: 3698: 3695: 3692: 3689: 3686: 3683: 3680: 3677: 3674: 3664: 3657: 3652: 3649: 3643: 3642: 3635: 3624: 3621: 3618: 3615: 3612: 3609: 3606: 3603: 3600: 3597: 3594: 3584: 3577: 3572: 3569: 3563: 3562: 3551: 3540: 3537: 3534: 3531: 3528: 3525: 3522: 3519: 3516: 3513: 3510: 3500: 3493: 3488: 3485: 3479: 3478: 3471:Center of mass 3463: 3452: 3449: 3446: 3443: 3440: 3437: 3434: 3431: 3421: 3414: 3409: 3406: 3400: 3399: 3388: 3377: 3374: 3371: 3368: 3365: 3355: 3348: 3343: 3340: 3334: 3333: 3330: 3327: 3318: 3315: 3313: 3310: 3291: 3288: 3280: 3272: 3269: 3261: 3253: 3250: 3225: 3222: 3214: 3206: 3203: 3195: 3187: 3184: 3169:Brocard points 3167:Main article: 3164: 3163:Brocard points 3161: 3159: 3156: 3143: 3142: 3129: 3124: 3120: 3116: 3113: 3110: 3107: 3104: 3101: 3098: 3095: 3091: 3087: 3079: 3077: 3072: 3069: 3064: 3061: 3058: 3055: 3052: 3049: 3048: 3041: 3037: 3033: 3030: 3027: 3024: 3019: or  3014: 3010: 3006: 3003: 3000: 2997: 2982: 2978: 2970: 2966: 2962: 2959: 2956: 2953: 2948: 2944: 2940: 2935: 2931: 2925: or  2918: 2914: 2910: 2907: 2904: 2901: 2896: 2892: 2888: 2883: 2879: 2863: 2861: 2858: 2857: 2854: 2850: 2846: 2843: 2840: 2837: 2828: 2824: 2820: 2816: 2812: 2809: 2806: 2803: 2798: 2794: 2790: 2785: 2781: 2771: 2769: 2766: 2765: 2763: 2758: 2755: 2752: 2749: 2746: 2743: 2740: 2737: 2734: 2719: 2716: 2697: 2693: 2687: 2684: 2679: 2676: 2672: 2668: 2665: 2662: 2658: 2652: 2649: 2644: 2641: 2637: 2633: 2630: 2627: 2623: 2617: 2614: 2609: 2606: 2602: 2598: 2595: 2537: 2534: 2513: 2510: 2507: 2504: 2501: 2498: 2495: 2492: 2489: 2486: 2484: 2482: 2479: 2474: 2470: 2466: 2461: 2457: 2453: 2448: 2444: 2440: 2437: 2434: 2431: 2429: 2427: 2424: 2419: 2415: 2411: 2406: 2402: 2398: 2393: 2389: 2385: 2382: 2379: 2376: 2374: 2372: 2369: 2366: 2363: 2360: 2357: 2354: 2351: 2348: 2347: 2323: 2320: 2317: 2314: 2311: 2308: 2305: 2302: 2297: 2293: 2289: 2286: 2284: 2282: 2277: 2272: 2267: 2263: 2259: 2254: 2250: 2246: 2241: 2237: 2233: 2230: 2225: 2218: 2214: 2210: 2207: 2205: 2203: 2198: 2191: 2187: 2183: 2180: 2177: 2174: 2169: 2165: 2161: 2158: 2155: 2152: 2147: 2143: 2139: 2136: 2133: 2128: 2123: 2120: 2117: 2114: 2112: 2110: 2107: 2104: 2101: 2098: 2095: 2092: 2089: 2086: 2083: 2080: 2077: 2076: 2051: 2045: 2041: 2037: 2032: 2028: 2024: 2019: 2015: 2010: 2006: 2003: 1999: 1995: 1992: 1989: 1986: 1983: 1979: 1975: 1953: 1950: 1945: 1941: 1937: 1932: 1928: 1924: 1919: 1915: 1911: 1908: 1905: 1902: 1897: 1893: 1889: 1884: 1880: 1876: 1871: 1867: 1863: 1860: 1857: 1854: 1849: 1845: 1841: 1836: 1832: 1828: 1823: 1819: 1815: 1812: 1791: 1788: 1786: 1783: 1698: 1695: 1694: 1693: 1692: 1691: 1628: 1623: 1619: 1615: 1612: 1609: 1606: 1601: 1597: 1593: 1588: 1584: 1579: 1574: 1570: 1566: 1563: 1560: 1557: 1552: 1548: 1544: 1539: 1535: 1530: 1525: 1521: 1517: 1514: 1511: 1508: 1503: 1499: 1495: 1490: 1486: 1475: 1474: 1473: 1472: 1468: 1462: 1451: 1446: 1442: 1438: 1433: 1429: 1425: 1420: 1416: 1411: 1406: 1402: 1398: 1393: 1389: 1385: 1380: 1376: 1371: 1366: 1362: 1358: 1353: 1349: 1345: 1340: 1336: 1313: 1306: 1299: 1292: 1285: 1266: 1263: 1244: 1241: 1238: 1235: 1232: 1229: 1225: 1222: 1219: 1216: 1213: 1210: 1206: 1203: 1200: 1197: 1194: 1191: 1167: 1162: 1124: 1120: 1116: 1112: 1108: 1103: 1099: 1095: 1091: 1087: 1082: 1078: 1074: 1070: 1053: 1036: 1031: 1026: 1010: 1009:Default domain 1007: 989: 986: 956: 953: 928: 925: 922: 919: 916: 913: 910: 907: 880: 877: 874: 871: 868: 865: 862: 859: 856: 853: 848: 844: 820: 817: 811: 808: 805: 802: 799: 796: 793: 790: 785: 781: 737: 734: 731: 728: 725: 722: 719: 716: 713: 710: 707: 704: 701: 698: 695: 692: 689: 686: 683: 680: 677: 674: 671: 668: 665: 662: 637:If a non-zero 635: 634: 623: 620: 617: 614: 611: 608: 605: 602: 599: 596: 593: 590: 587: 584: 581: 578: 575: 572: 561: 538: 535: 532: 529: 526: 523: 520: 517: 512: 508: 504: 501: 498: 495: 492: 489: 486: 483: 480: 477: 474: 471: 444: 441: 426: 422: 401: 398: 395: 392: 368: 346: 342: 321: 318: 315: 312: 303:is denoted by 279:Gergonne point 261: 258: 241:Brocard points 202:ancient Greeks 148:, lies on the 129: 120:(intersect at 112: 94: 85:(intersect at 77: 56: 44: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 9318: 9307: 9304: 9303: 9301: 9291: 9287: 9283: 9280: 9276: 9272: 9270: 9266: 9262: 9259: 9257: 9253: 9251: 9247: 9246: 9242: 9234: 9230: 9226: 9222: 9218: 9214: 9209: 9204: 9200: 9196: 9192: 9185: 9182: 9177: 9173: 9169: 9165: 9161: 9157: 9153: 9149: 9145: 9138: 9135: 9130: 9124: 9120: 9116: 9112: 9111: 9103: 9101: 9097: 9092: 9088: 9084: 9078: 9074: 9073: 9065: 9062: 9059:, article #18 9056: 9052: 9045: 9038: 9035: 9029: 9024: 9017: 9014: 9002: 8998: 8991: 8988: 8976: 8972: 8965: 8962: 8957: 8953: 8949: 8945: 8941: 8937: 8933: 8926: 8923: 8919: 8914: 8911: 8899: 8895: 8888: 8885: 8873: 8869: 8865: 8859: 8856: 8844: 8840: 8836: 8830: 8827: 8822: 8818: 8814: 8810: 8806: 8802: 8798: 8792: 8789: 8785: 8774: 8770: 8764: 8761: 8752: 8748: 8744: 8738: 8735: 8728: 8723: 8720: 8718: 8715: 8713: 8710: 8708: 8705: 8703: 8700: 8698: 8695: 8694: 8689: 8687: 8685: 8680: 8678: 8674: 8669: 8667: 8663: 8659: 8655: 8647: 8645: 8643: 8639: 8635: 8631: 8623: 8621: 8616: 8612: 8608: 8586: 8580: 8577: 8574: 8571: 8568: 8562: 8545: 8542: 8539: 8536: 8533: 8527: 8510: 8507: 8504: 8501: 8498: 8492: 8472: 8466: 8463: 8460: 8457: 8454: 8448: 8431: 8428: 8425: 8422: 8419: 8413: 8396: 8393: 8390: 8387: 8384: 8378: 8354: 8351: 8337: 8323: 8303: 8300: 8297: 8294: 8291: 8281: 8277: 8273: 8263: 8261: 8258: 8236: 8233: 8230: 8227: 8224: 8221: 8218: 8215: 8212: 8209: 8204: 8199: 8196: 8193: 8190: 8187: 8184: 8181: 8176: 8171: 8168: 8165: 8162: 8159: 8156: 8153: 8143: 8140: 8128: 8125: 8122: 8119: 8116: 8113: 8110: 8105: 8100: 8097: 8094: 8091: 8088: 8085: 8082: 8079: 8076: 8073: 8068: 8063: 8060: 8057: 8054: 8051: 8048: 8045: 8035: 8032: 8020: 8017: 8014: 8011: 8008: 8005: 8002: 7997: 7992: 7989: 7986: 7983: 7980: 7977: 7974: 7969: 7964: 7961: 7958: 7955: 7952: 7949: 7946: 7943: 7940: 7937: 7927: 7924: 7907: 7904: 7901: 7897: 7891: 7888: 7885: 7881: 7875: 7872: 7869: 7841: 7821: 7813: 7810: 7802: 7799: 7789: 7786: 7783: 7780: 7777: 7774: 7771: 7764: 7756: 7753: 7743: 7740: 7737: 7734: 7731: 7728: 7725: 7722: 7719: 7716: 7709: 7691: 7688: 7685: 7679: 7674: 7668: 7665: 7662: 7659: 7656: 7650: 7642: 7637: 7629: 7627: 7621: 7605: 7599: 7596: 7593: 7590: 7587: 7581: 7577: 7574: 7568: 7565: 7562: 7559: 7556: 7550: 7546: 7543: 7537: 7534: 7531: 7528: 7525: 7519: 7515: 7495: 7493: 7490: 7486: 7482: 7476: 7472: 7468: 7458: 7438: 7427: 7411: 7404: 7393: 7385: 7382: 7379: 7371: 7368: 7365: 7354: 7347: 7336: 7328: 7325: 7322: 7314: 7311: 7308: 7297: 7291: 7286: 7280: 7277: 7274: 7271: 7268: 7262: 7254: 7240: 7238: 7225: 7222: 7217: 7209: 7206: 7203: 7200: 7197: 7189: 7186: 7178: 7175: 7172: 7156: 7140: 7134: 7131: 7128: 7125: 7122: 7113: 7110: 7107: 7104: 7091: 7088: 7085: 7082: 7079: 7073: 7070: 7064: 7061: 7058: 7055: 7052: 7049: 7046: 7043: 7037: 7027: 7018: 7006: 7004: 6990: 6984: 6981: 6978: 6975: 6972: 6966: 6963: 6957: 6954: 6951: 6948: 6945: 6939: 6936: 6930: 6927: 6924: 6921: 6918: 6912: 6889: 6886: 6883: 6880: 6877: 6871: 6864: 6861: 6858: 6855: 6852: 6846: 6840: 6832: 6829: 6826: 6823: 6820: 6814: 6805: 6802: 6799: 6796: 6793: 6770: 6767: 6764: 6761: 6758: 6755: 6742: 6739: 6736: 6733: 6730: 6724: 6721: 6718: 6712: 6709: 6706: 6703: 6700: 6694: 6686: 6674: 6672: 6668: 6648: 6637: 6627: 6624: 6621: 6618: 6610: 6607: 6604: 6593: 6590: 6584: 6579: 6573: 6570: 6567: 6564: 6561: 6555: 6543: 6541: 6539: 6509: 6506: 6503: 6500: 6497: 6491: 6488: 6486: 6475: 6472: 6469: 6453: 6450: 6447: 6444: 6441: 6435: 6432: 6430: 6422: 6419: 6416: 6413: 6410: 6404: 6391: 6387: 6374: 6370:Miscellaneous 6369: 6367: 6357: 6345: 6343: 6320: 6314: 6289: 6283: 6280: 6274: 6268: 6265: 6259: 6253: 6245: 6233: 6231: 6224: 6220: 6216: 6206: 6194: 6192: 6182: 6170: 6168: 6166: 6158: 6153: 6146: 6130: 6127: 6116: 6113: 6108: 6104: 6100: 6083: 6080: 6074: 6071: 6065: 6062: 6056: 6053: 6050: 6047: 6041: 6038: 6032: 6029: 6020: 6019:Morley center 6017: 6012: 6008: 6004: 5987: 5984: 5981: 5978: 5975: 5972: 5969: 5966: 5960: 5957: 5948: 5945: 5940: 5936: 5932: 5915: 5912: 5909: 5906: 5903: 5896: 5888: 5885: 5882: 5876: 5864: 5861: 5856: 5852: 5849: 5832: 5829: 5823: 5818: 5814: 5804: 5801: 5796: 5792: 5788: 5774: 5771: 5765: 5762: 5756: 5753: 5747: 5744: 5738: 5735: 5729: 5726: 5720: 5717: 5708: 5705: 5700: 5696: 5692: 5675: 5672: 5666: 5663: 5654: 5651: 5646: 5642: 5638: 5621: 5618: 5612: 5609: 5606: 5600: 5597: 5591: 5588: 5579: 5576: 5571: 5567: 5563: 5544: 5540: 5536: 5531: 5527: 5523: 5518: 5514: 5510: 5506: 5495: 5492: 5487: 5483: 5479: 5460: 5456: 5452: 5447: 5443: 5439: 5434: 5430: 5423: 5414: 5411: 5406: 5402: 5398: 5381: 5378: 5375: 5372: 5369: 5366: 5363: 5359: 5348: 5345: 5340: 5336: 5332: 5315: 5312: 5309: 5306: 5303: 5297: 5288: 5284: 5281: 5274: 5267: 5248: 5244: 5240: 5235: 5231: 5225: 5222: 5216: 5208: 5204: 5200: 5195: 5191: 5185: 5182: 5176: 5168: 5164: 5160: 5155: 5151: 5145: 5142: 5132: 5129: 5125: 5123: 5122:Steiner point 5120: 5115: 5112: 5111: 5107: 5083: 5080: 5074: 5071: 5065: 5062: 5059: 5050: 5047: 5041: 5038: 5032: 5029: 5026: 5017: 5014: 5008: 5005: 4999: 4996: 4983: 4980: 4974: 4971: 4965: 4962: 4959: 4950: 4947: 4941: 4938: 4932: 4929: 4926: 4917: 4914: 4908: 4905: 4899: 4896: 4885: 4881: 4877: 4873: 4871: 4868: 4863: 4856: 4853: 4852: 4848: 4844: 4820: 4817: 4811: 4808: 4802: 4799: 4796: 4787: 4784: 4778: 4775: 4769: 4766: 4763: 4754: 4751: 4745: 4742: 4736: 4733: 4720: 4717: 4711: 4708: 4702: 4699: 4696: 4687: 4684: 4678: 4675: 4669: 4666: 4663: 4654: 4651: 4645: 4642: 4636: 4633: 4622: 4618: 4614: 4610: 4608: 4605: 4600: 4593: 4590: 4589: 4585: 4571: 4562: 4559: 4553: 4550: 4544: 4541: 4538: 4529: 4526: 4520: 4517: 4511: 4508: 4505: 4496: 4493: 4487: 4484: 4478: 4475: 4468: 4465: 4461: 4459: 4456: 4451: 4448: 4447: 4443: 4426: 4423: 4420: 4414: 4411: 4408: 4405: 4402: 4396: 4393: 4390: 4384: 4381: 4378: 4375: 4372: 4366: 4363: 4360: 4354: 4351: 4348: 4345: 4338: 4335: 4331: 4329: 4326: 4321: 4318: 4317: 4313: 4296: 4293: 4290: 4284: 4281: 4278: 4272: 4269: 4266: 4260: 4257: 4254: 4248: 4245: 4242: 4236: 4233: 4226: 4222: 4218: 4214: 4212: 4209: 4204: 4201: 4200: 4196: 4193:point of the 4192: 4189: 4172: 4169: 4166: 4163: 4160: 4154: 4148: 4145: 4142: 4139: 4136: 4130: 4124: 4121: 4118: 4115: 4112: 4102: 4099: 4095: 4093: 4090: 4085: 4082: 4081: 4077: 4061: 4057: 4054: 4051: 4048: 4045: 4039: 4034: 4030: 4027: 4024: 4021: 4018: 4012: 4007: 4003: 4000: 3997: 3994: 3991: 3981: 3977: 3973: 3969: 3967: 3964: 3959: 3956: 3955: 3951: 3934: 3931: 3928: 3925: 3922: 3917: 3914: 3908: 3902: 3899: 3896: 3893: 3890: 3885: 3882: 3876: 3870: 3867: 3864: 3861: 3858: 3853: 3850: 3840: 3836: 3832: 3828: 3826: 3823: 3818: 3815: 3814: 3810: 3796: 3793: 3790: 3787: 3784: 3777: 3774: 3770: 3768: 3765: 3760: 3757: 3756: 3752: 3735: 3732: 3729: 3723: 3720: 3717: 3711: 3708: 3705: 3699: 3696: 3693: 3687: 3684: 3681: 3675: 3672: 3665: 3662: 3658: 3656: 3653: 3648: 3645: 3644: 3640: 3636: 3622: 3619: 3616: 3613: 3610: 3607: 3604: 3601: 3598: 3595: 3592: 3585: 3582: 3578: 3576: 3573: 3568: 3565: 3564: 3560: 3556: 3552: 3538: 3535: 3532: 3529: 3526: 3523: 3520: 3517: 3514: 3511: 3508: 3501: 3498: 3494: 3492: 3489: 3484: 3481: 3480: 3476: 3472: 3468: 3464: 3450: 3447: 3444: 3441: 3438: 3435: 3432: 3429: 3422: 3419: 3415: 3413: 3410: 3405: 3402: 3401: 3397: 3393: 3389: 3375: 3372: 3369: 3366: 3363: 3356: 3353: 3349: 3347: 3344: 3339: 3336: 3335: 3331: 3328: 3326:Name; Symbol 3322: 3316: 3311: 3309: 3305: 3289: 3286: 3278: 3270: 3267: 3259: 3251: 3248: 3223: 3220: 3212: 3204: 3201: 3193: 3185: 3182: 3170: 3162: 3157: 3155: 3153: 3122: 3118: 3114: 3111: 3108: 3105: 3102: 3099: 3096: 3093: 3070: 3067: 3062: 3059: 3053: 3050: 3039: 3035: 3031: 3028: 3025: 3022: 3012: 3008: 3004: 3001: 2998: 2995: 2968: 2964: 2960: 2957: 2954: 2951: 2946: 2942: 2938: 2933: 2929: 2916: 2912: 2908: 2905: 2902: 2899: 2894: 2890: 2886: 2881: 2877: 2859: 2852: 2848: 2844: 2841: 2838: 2835: 2818: 2814: 2810: 2807: 2804: 2801: 2796: 2792: 2788: 2783: 2779: 2767: 2761: 2756: 2750: 2747: 2744: 2741: 2738: 2732: 2725: 2724: 2723: 2717: 2715: 2708: 2695: 2691: 2685: 2682: 2677: 2674: 2670: 2666: 2663: 2660: 2656: 2650: 2647: 2642: 2639: 2635: 2631: 2628: 2625: 2621: 2615: 2612: 2607: 2604: 2600: 2596: 2593: 2585: 2582:AA', BB', CC' 2578: 2571: 2564: 2545: 2535: 2533: 2508: 2505: 2502: 2499: 2496: 2490: 2487: 2485: 2472: 2468: 2464: 2459: 2455: 2451: 2446: 2442: 2435: 2432: 2430: 2417: 2413: 2409: 2404: 2400: 2396: 2391: 2387: 2380: 2377: 2375: 2367: 2364: 2361: 2358: 2355: 2349: 2318: 2315: 2312: 2309: 2306: 2300: 2295: 2291: 2287: 2285: 2265: 2261: 2257: 2252: 2248: 2244: 2239: 2235: 2228: 2216: 2212: 2208: 2206: 2189: 2181: 2178: 2172: 2167: 2159: 2156: 2150: 2145: 2137: 2134: 2121: 2118: 2115: 2113: 2105: 2102: 2099: 2096: 2093: 2090: 2087: 2084: 2078: 2049: 2043: 2039: 2035: 2030: 2026: 2022: 2017: 2013: 2008: 2004: 2001: 1997: 1993: 1990: 1987: 1984: 1981: 1977: 1973: 1964: 1951: 1943: 1939: 1935: 1930: 1926: 1922: 1917: 1913: 1906: 1903: 1895: 1891: 1887: 1882: 1878: 1874: 1869: 1865: 1858: 1855: 1847: 1843: 1839: 1834: 1830: 1826: 1821: 1817: 1810: 1802: 1799: 1789: 1784: 1782: 1780: 1774: 1770: 1766: 1759: 1755: 1751: 1745: 1741: 1735: 1731: 1725: 1721: 1715: 1709: 1705: 1696: 1688: 1682: 1678: 1672: 1668: 1662: 1658: 1653: 1648: 1643: 1642: 1641: 1640: 1639: 1626: 1621: 1617: 1613: 1610: 1607: 1604: 1599: 1595: 1591: 1586: 1582: 1577: 1572: 1568: 1564: 1561: 1558: 1555: 1550: 1546: 1542: 1537: 1533: 1528: 1523: 1519: 1515: 1512: 1509: 1506: 1501: 1497: 1493: 1488: 1484: 1467: 1463: 1449: 1444: 1440: 1436: 1431: 1427: 1423: 1418: 1414: 1409: 1404: 1400: 1396: 1391: 1387: 1383: 1378: 1374: 1369: 1364: 1360: 1356: 1351: 1347: 1343: 1338: 1334: 1324: 1319: 1312: 1305: 1298: 1291: 1284: 1280: 1279: 1278: 1277: 1276: 1273: 1264: 1262: 1259: 1242: 1239: 1236: 1233: 1230: 1227: 1223: 1220: 1217: 1214: 1211: 1208: 1204: 1201: 1198: 1195: 1192: 1189: 1165: 1148: 1144: 1122: 1118: 1114: 1110: 1106: 1101: 1097: 1093: 1089: 1085: 1080: 1076: 1072: 1068: 1059: 1052: 1034: 1029: 1008: 1006: 987: 984: 954: 951: 923: 920: 917: 914: 911: 905: 896: 878: 875: 872: 866: 863: 860: 857: 854: 846: 842: 818: 815: 809: 803: 800: 797: 794: 791: 783: 779: 770: 765: 763: 755: 749: 732: 729: 726: 723: 720: 714: 711: 705: 702: 699: 696: 693: 687: 684: 678: 675: 672: 669: 666: 660: 652: 621: 615: 612: 609: 606: 603: 597: 594: 588: 585: 582: 579: 576: 570: 562: 557: 533: 530: 527: 524: 521: 515: 510: 506: 502: 496: 493: 490: 487: 484: 481: 478: 475: 469: 462:Homogeneity: 461: 460: 459: 450: 442: 440: 424: 420: 396: 390: 382: 366: 344: 340: 316: 310: 302: 298: 297: 292: 286: 284: 280: 276: 275:Lemoine point 272: 268: 259: 257: 255: 254: 249: 244: 242: 238: 234: 230: 226: 222: 218: 214: 209: 207: 206:constructions 203: 199: 195: 191: 187: 183: 179: 175: 171: 167: 163: 151: 140: 137:(centered at 136: 123: 119: 105: 101: 88: 84: 71: 67: 63: 53: 41: 37: 33: 19: 9198: 9194: 9184: 9151: 9147: 9137: 9119:10.1142/7740 9109: 9071: 9064: 9054: 9050: 9037: 9016: 9004:. Retrieved 9000: 8990: 8978:. Retrieved 8974: 8964: 8939: 8935: 8925: 8913: 8901:. Retrieved 8897: 8887: 8875:. Retrieved 8871: 8858: 8846:. Retrieved 8842: 8829: 8804: 8800: 8791: 8782: 8776:. Retrieved 8763: 8750: 8746: 8742: 8737: 8697:Central line 8681: 8670: 8651: 8627: 8614: 8610: 8606: 8279: 8275: 8271: 8267: 8259: 7842: 7643: 7635: 7633: 7499: 7488: 7484: 7480: 7474: 7470: 7466: 7459: 7255: 7244: 7025: 7016: 7010: 6684: 6678: 6669: 6547: 6389: 6385: 6378: 6355: 6354:is called a 6349: 6243: 6237: 6222: 6218: 6214: 6204: 6203:is called a 6198: 6180: 6179:is called a 6174: 6164: 6162: 6106: 6010: 5938: 5854: 5794: 5698: 5644: 5569: 5564:early 1990s 5485: 5413:Exeter point 5404: 5338: 5278: 5127: 5113: 4879: 4875: 4861: 4854: 4616: 4612: 4598: 4591: 4463: 4458:Fermat point 4449: 4333: 4319: 4220: 4216: 4202: 4097: 4083: 3975: 3971: 3957: 3834: 3830: 3816: 3772: 3758: 3660: 3646: 3580: 3566: 3496: 3491:Circumcenter 3482: 3417: 3403: 3351: 3337: 3332:Description 3306: 3172: 3158:Non-examples 3152:Fermat point 3144: 2721: 2718:Fermat point 2709: 2586: 2576: 2569: 2562: 2543: 2539: 1965: 1803: 1797: 1793: 1790:Circumcenter 1772: 1768: 1764: 1757: 1753: 1749: 1743: 1739: 1733: 1729: 1723: 1719: 1713: 1707: 1703: 1700: 1686: 1680: 1676: 1670: 1666: 1660: 1656: 1646: 1476: 1465: 1322: 1310: 1303: 1296: 1289: 1282: 1281:The centers 1271: 1268: 1257: 1255:This region 1050: 1012: 897: 766: 761: 750: 636: 555: 553:and for all 446: 300: 294: 287: 267:Fermat point 263: 251: 245: 210: 190:circumcenter 169: 165: 159: 104:circumcircle 51: 36: 8671:Centers of 6679:A function 6466:since  5494:Parry point 4845:Centers of 4092:Mittenpunkt 3966:Nagel point 3575:Orthocenter 2551:and vertex 237:translation 217:equivariant 198:orthocenter 122:orthocenter 9284:Paul Yiu, 9208:2004.01677 9057:(1): 1–35. 9028:1608.08190 8778:2009-05-23 8722:Euler line 8673:tetrahedra 7017:normalized 229:reflection 150:Euler line 9273:Ed Pegg, 9233:214795185 9225:1420-9012 9201:(2): 81. 9176:122725235 9168:1422-6383 9091:663096629 8956:0002-9890 8677:simplices 8642:homothecy 8638:homothety 8352:α 8338:β 8324:γ 8304:α 8298:β 8292:γ 8234:⁡ 8225:⁡ 8213:⁡ 8197:⁡ 8191:− 8185:⁡ 8169:⁡ 8163:− 8157:⁡ 8141:∡ 8126:⁡ 8120:− 8114:⁡ 8098:⁡ 8089:⁡ 8077:⁡ 8061:⁡ 8055:− 8049:⁡ 8033:∡ 8018:⁡ 8012:− 8006:⁡ 7990:⁡ 7984:− 7978:⁡ 7962:⁡ 7953:⁡ 7941:⁡ 7925:∡ 7905:⁡ 7889:⁡ 7873:⁡ 7861:△ 7811:∡ 7800:∡ 7796:if either 7787:⁡ 7781:− 7775:⁡ 7754:∡ 7741:⁡ 7732:⁡ 7720:⁡ 7702:△ 7689:⁡ 7419:otherwise 7412:β 7355:γ 7298:α 7187:− 6812:→ 6722:− 6645:otherwise 6622:≥ 6608:≥ 6591:− 6544:Excenters 6075:⁡ 6057:⁡ 6033:⁡ 5982:− 5913:− 5824:⁡ 5772:− 5757:⁡ 5739:⁡ 5721:⁡ 5667:⁡ 5613:⁡ 5592:⁡ 5537:− 5524:− 5453:− 5379:⁡ 5367:⁡ 5241:− 5201:− 5161:− 5081:π 5066:⁡ 5048:π 5033:⁡ 5015:π 5000:⁡ 4981:π 4975:− 4966:⁡ 4948:π 4942:− 4933:⁡ 4915:π 4909:− 4900:⁡ 4847:inversion 4818:π 4812:− 4803:⁡ 4785:π 4779:− 4770:⁡ 4752:π 4746:− 4737:⁡ 4718:π 4703:⁡ 4685:π 4670:⁡ 4652:π 4637:⁡ 4560:π 4545:⁡ 4527:π 4512:⁡ 4494:π 4479:⁡ 4424:− 4415:⁡ 4409:− 4394:− 4385:⁡ 4379:− 4364:− 4355:⁡ 4349:− 4191:Symmedian 4170:− 4146:− 4122:− 4055:− 4028:− 4001:− 3932:− 3900:− 3868:− 3733:− 3724:⁡ 3709:− 3700:⁡ 3685:− 3676:⁡ 3639:altitudes 3620:⁡ 3608:⁡ 3596:⁡ 3536:⁡ 3524:⁡ 3512:⁡ 3115:π 3090:⟺ 3068:π 3054:⁡ 3032:π 3005:π 2981:⟺ 2845:π 2827:⟺ 2683:π 2667:⁡ 2648:π 2632:⁡ 2613:π 2597:⁡ 2465:− 2410:− 2258:− 2173:− 2036:− 1936:− 1888:− 1840:− 1424:≤ 1384:≤ 1344:≤ 1231:≤ 1212:≤ 1193:≤ 769:bijective 762:cyclicity 213:invariant 118:Altitudes 9300:Category 8690:See also 8684:centroid 8137:if  8029:if  7921:if  7750:if  7698:if  7473: : 7469: : 7362:if  7305:if  7023:so that 6601:if  6226:, where 3412:Centroid 3346:Incenter 2992:if  2873:if  2832:if  2775:if  2559:and let 1785:Examples 939:be 0 if 381:centroid 233:dilation 225:rotation 219:) under 194:incenter 186:centroid 178:triangle 162:geometry 87:centroid 70:incenter 66:incircle 8848:17 June 8821:2690608 7251:α, β, γ 7247:a, b, c 7245:Assume 7155:algebra 7100:for all 7021:a, b, c 7015:can be 6751:for all 6393:) then 6364:a, b, c 6336:⁠ 6307:⁠ 6189:a, b, c 3467:medians 2712:a, b, c 1652:scalene 1182:where 1180:⁠ 1151:⁠ 1139:a, b, c 1047:⁠ 1015:⁠ 1003:⁠ 974:⁠ 970:⁠ 941:⁠ 893:a, b, c 758:a, b, c 647:a, b, c 456:a, b, c 260:History 246:For an 176:in the 146:H, G, O 83:Medians 9231:  9223:  9174:  9166:  9125:  9089:  9079:  9006:25 May 8980:25 May 8954:  8903:1 July 8877:25 May 8819:  8753:≤ 2π/3 8640:, and 8560:  8552:  8525:  8517:  8446:  8438:  8411:  8403:  8349:  8341:  8335:  8327:  7895:  7879:  7117:  6305:where 3475:lamina 3282:  3276:  3263:  3257:  3216:  3210:  3197:  3191:  1326:where 1147:domain 1060:, are 558:> 0 359:where 281:, and 133:  131:  116:  114:  98:  96:  81:  79:  60:  58:  46:  9288:from 9277:from 9267:from 9229:S2CID 9203:arXiv 9172:S2CID 9047:(PDF) 9023:arXiv 8817:JSTOR 8729:Notes 7487:< 7483:< 7460:Then 6147:1992 6101:1978 6005:1961 5933:1987 5789:1985 5693:1987 5639:1989 5480:1986 5399:1985 3145:Then 2570:ABC' 1684:from 235:, or 182:plane 174:point 172:is a 9221:ISSN 9164:ISSN 9123:ISBN 9087:OCLC 9077:ISBN 9008:2009 8982:2009 8952:ISSN 8905:2009 8879:2009 8850:2022 7383:> 7369:> 7326:< 7312:< 7162:and 7108:> 6687:if 6548:Let 6379:Let 6358:if 3109:> 3026:> 2999:> 2939:> 2887:> 2839:> 2789:> 2722:Let 2566:and 2563:AB'C 2544:A'BC 2540:Let 1966:Let 1592:> 1543:> 1494:> 972:and 834:and 653:are 196:and 164:, a 102:and 64:and 9213:doi 9156:doi 9115:doi 8944:doi 8809:doi 8367:If 8316:is 8231:sec 8222:sec 8210:cos 8194:sec 8182:cos 8166:sec 8154:cos 8123:sec 8111:cos 8095:sec 8086:sec 8074:cos 8058:sec 8046:cos 8015:sec 8003:cos 7987:sec 7975:cos 7959:sec 7950:sec 7938:cos 7902:cos 7886:cos 7870:cos 7784:sec 7772:cos 7738:sec 7729:sec 7717:cos 7686:cos 7500:If 7028:= 0 6683:is 6213:△, 6110:360 6072:cos 6054:cos 6030:cos 6014:356 5942:192 5858:181 5815:sec 5798:179 5754:cos 5736:cos 5718:sec 5702:175 5664:sec 5648:174 5610:sec 5589:tan 5573:173 5489:111 5376:cos 5364:cos 5117:99 5063:sec 5030:sec 4997:sec 4963:sec 4930:sec 4897:sec 4800:sin 4767:sin 4734:sin 4700:sin 4667:sin 4634:sin 4542:csc 4509:csc 4476:csc 4412:cos 4382:cos 4352:cos 3721:cos 3697:cos 3673:cos 3617:sec 3605:sec 3593:sec 3533:cos 3521:cos 3509:cos 3469:. 3051:csc 2664:csc 2629:csc 2594:csc 2577:ABC 2528:so 1798:ABC 1137:so 1054:365 756:of 412:or 332:or 293:'s 208:. 180:'s 168:or 160:In 52:ABC 9302:: 9263:, 9227:. 9219:. 9211:. 9199:76 9197:. 9193:. 9170:. 9162:. 9152:55 9150:. 9146:. 9121:. 9099:^ 9085:. 9053:. 9049:. 8999:. 8973:. 8950:. 8940:85 8938:. 8934:. 8896:. 8870:. 8866:. 8841:. 8837:. 8815:. 8805:67 8803:. 8781:. 8771:. 8644:. 8636:, 8632:, 8613:, 8609:, 8278:, 8274:, 7506:af 6388:= 6366:. 6221:, 6217:, 6191:. 6167:. 5408:22 5342:21 4865:18 4858:17 4602:16 4595:15 4453:13 4323:11 4206:10 3641:. 3561:. 3477:. 3398:. 3154:. 2557:BC 2553:A' 2549:BC 1781:. 1771:, 1767:, 1756:= 1752:= 1742:= 1737:, 1732:= 1727:, 1722:= 1706:⊆ 1679:= 1674:, 1669:= 1664:, 1659:= 1469:13 1314:40 1309:, 1307:24 1302:, 1300:22 1295:, 1288:, 895:. 764:. 447:A 439:. 277:, 273:, 269:, 256:. 231:, 227:, 192:, 188:, 9292:. 9281:. 9235:. 9215:: 9205:: 9178:. 9158:: 9131:. 9117:: 9093:. 9055:6 9031:. 9025:: 9010:. 8984:. 8958:. 8946:: 8907:. 8881:. 8852:. 8823:. 8811:: 8751:C 8749:, 8747:B 8745:, 8743:A 8617:) 8615:a 8611:b 8607:c 8605:( 8601:f 8587:. 8584:) 8581:b 8578:, 8575:c 8572:, 8569:a 8566:( 8563:f 8556:| 8549:) 8546:c 8543:, 8540:a 8537:, 8534:b 8531:( 8528:f 8521:| 8514:) 8511:a 8508:, 8505:b 8502:, 8499:c 8496:( 8493:f 8473:, 8470:) 8467:c 8464:, 8461:b 8458:, 8455:a 8452:( 8449:f 8442:| 8435:) 8432:a 8429:, 8426:c 8423:, 8420:b 8417:( 8414:f 8407:| 8400:) 8397:b 8394:, 8391:a 8388:, 8385:c 8382:( 8379:f 8369:f 8355:. 8345:| 8331:| 8301:: 8295:: 8282:) 8280:a 8276:b 8272:c 8270:( 8237:B 8228:A 8219:+ 8216:C 8205:: 8200:B 8188:B 8177:: 8172:A 8160:A 8144:C 8129:C 8117:C 8106:: 8101:A 8092:C 8083:+ 8080:B 8069:: 8064:A 8052:A 8036:B 8021:C 8009:C 7998:: 7993:B 7981:B 7970:: 7965:C 7956:B 7947:+ 7944:A 7928:A 7908:C 7898:: 7892:B 7882:: 7876:A 7822:. 7814:C 7803:B 7790:A 7778:A 7765:, 7757:A 7744:C 7735:B 7726:+ 7723:A 7710:, 7692:A 7680:{ 7675:= 7672:) 7669:c 7666:, 7663:b 7660:, 7657:a 7654:( 7651:f 7639:3 7636:X 7624:f 7606:. 7603:) 7600:b 7597:, 7594:a 7591:, 7588:c 7585:( 7582:f 7578:c 7575:: 7572:) 7569:a 7566:, 7563:c 7560:, 7557:b 7554:( 7551:f 7547:b 7544:: 7541:) 7538:c 7535:, 7532:b 7529:, 7526:a 7523:( 7520:f 7516:a 7502:f 7489:c 7485:b 7481:a 7475:γ 7471:β 7467:α 7462:f 7439:. 7436:) 7428:a 7425:( 7405:, 7402:) 7394:a 7391:( 7386:c 7380:a 7372:b 7366:a 7348:, 7345:) 7337:a 7334:( 7329:c 7323:a 7315:b 7309:a 7292:{ 7287:= 7284:) 7281:c 7278:, 7275:b 7272:, 7269:a 7266:( 7263:f 7226:. 7223:f 7218:3 7214:) 7210:c 7207:+ 7204:b 7201:+ 7198:a 7195:( 7190:1 7183:) 7179:c 7176:b 7173:a 7170:( 7160:f 7141:. 7138:) 7135:c 7132:, 7129:b 7126:, 7123:a 7120:( 7114:, 7111:0 7105:t 7095:) 7092:c 7089:, 7086:b 7083:, 7080:a 7077:( 7074:f 7071:= 7068:) 7065:c 7062:t 7059:, 7056:b 7053:t 7050:, 7047:a 7044:t 7041:( 7038:f 7026:n 7013:f 6991:. 6988:) 6985:b 6982:, 6979:a 6976:, 6973:c 6970:( 6967:f 6964:: 6961:) 6958:a 6955:, 6952:c 6949:, 6946:b 6943:( 6940:f 6937:: 6934:) 6931:c 6928:, 6925:b 6922:, 6919:a 6916:( 6913:f 6893:) 6890:b 6887:, 6884:a 6881:, 6878:c 6875:( 6872:f 6868:) 6865:a 6862:, 6859:c 6856:, 6853:b 6850:( 6847:f 6841:2 6837:) 6833:c 6830:, 6827:b 6824:, 6821:a 6818:( 6815:f 6809:) 6806:c 6803:, 6800:b 6797:, 6794:a 6791:( 6771:. 6768:c 6765:, 6762:b 6759:, 6756:a 6746:) 6743:b 6740:, 6737:c 6734:, 6731:a 6728:( 6725:f 6719:= 6716:) 6713:c 6710:, 6707:b 6704:, 6701:a 6698:( 6695:f 6681:f 6649:. 6638:1 6628:, 6625:c 6619:a 6611:b 6605:a 6594:1 6585:{ 6580:= 6577:) 6574:c 6571:, 6568:b 6565:, 6562:a 6559:( 6556:f 6513:) 6510:a 6507:, 6504:c 6501:, 6498:b 6495:( 6492:f 6489:= 6479:) 6476:b 6473:= 6470:a 6462:( 6457:) 6454:c 6451:, 6448:a 6445:, 6442:b 6439:( 6436:f 6433:= 6426:) 6423:c 6420:, 6417:b 6414:, 6411:a 6408:( 6405:f 6390:b 6386:a 6381:f 6360:P 6352:P 6340:X 6324:) 6321:X 6318:( 6315:f 6293:) 6290:C 6287:( 6284:f 6281:: 6278:) 6275:B 6272:( 6269:f 6266:: 6263:) 6260:A 6257:( 6254:f 6240:P 6228:△ 6223:c 6219:b 6215:a 6209:P 6201:P 6185:P 6177:P 6131:a 6128:A 6107:X 6084:3 6081:C 6066:3 6063:B 6051:2 6048:+ 6042:3 6039:A 6011:X 5991:) 5988:c 5985:b 5979:b 5976:a 5973:+ 5970:a 5967:c 5964:( 5961:c 5958:b 5939:X 5916:a 5910:c 5907:+ 5904:b 5897:2 5893:) 5889:c 5886:+ 5883:b 5880:( 5877:a 5855:X 5833:4 5830:A 5819:4 5795:X 5775:1 5766:2 5763:C 5748:2 5745:B 5730:2 5727:A 5699:X 5676:2 5673:A 5645:X 5622:2 5619:A 5607:+ 5601:2 5598:A 5570:X 5545:2 5541:c 5532:2 5528:b 5519:2 5515:a 5511:2 5507:a 5486:X 5466:) 5461:4 5457:a 5448:4 5444:c 5440:+ 5435:4 5431:b 5427:( 5424:a 5405:X 5382:C 5373:+ 5370:B 5360:1 5339:X 5319:) 5316:c 5313:, 5310:b 5307:, 5304:a 5301:( 5298:f 5249:2 5245:b 5236:2 5232:a 5226:b 5223:a 5217:: 5209:2 5205:a 5196:2 5192:c 5186:a 5183:c 5177:: 5169:2 5165:c 5156:2 5152:b 5146:c 5143:b 5128:S 5114:X 5090:) 5084:3 5075:+ 5072:C 5069:( 5060:: 5057:) 5051:3 5042:+ 5039:B 5036:( 5027:: 5024:) 5018:3 5009:+ 5006:A 5003:( 4990:) 4984:3 4972:C 4969:( 4960:: 4957:) 4951:3 4939:B 4936:( 4927:: 4924:) 4918:3 4906:A 4903:( 4882:′ 4880:N 4876:N 4862:X 4855:X 4827:) 4821:3 4809:C 4806:( 4797:: 4794:) 4788:3 4776:B 4773:( 4764:: 4761:) 4755:3 4743:A 4740:( 4727:) 4721:3 4712:+ 4709:C 4706:( 4697:: 4694:) 4688:3 4679:+ 4676:B 4673:( 4664:: 4661:) 4655:3 4646:+ 4643:A 4640:( 4619:′ 4617:S 4613:S 4599:X 4592:X 4572:. 4569:) 4563:3 4554:+ 4551:C 4548:( 4539:: 4536:) 4530:3 4521:+ 4518:B 4515:( 4506:: 4503:) 4497:3 4488:+ 4485:A 4482:( 4464:X 4450:X 4430:) 4427:B 4421:A 4418:( 4406:1 4403:: 4400:) 4397:A 4391:C 4388:( 4376:1 4373:: 4370:) 4367:C 4361:B 4358:( 4346:1 4334:F 4320:X 4300:) 4297:b 4294:+ 4291:a 4288:( 4285:b 4282:a 4279:: 4276:) 4273:a 4270:+ 4267:c 4264:( 4261:a 4258:c 4255:: 4252:) 4249:c 4246:+ 4243:b 4240:( 4237:c 4234:b 4221:p 4217:S 4203:X 4176:) 4173:c 4167:b 4164:+ 4161:a 4158:( 4155:: 4152:) 4149:b 4143:a 4140:+ 4137:c 4134:( 4131:: 4128:) 4125:a 4119:c 4116:+ 4113:b 4110:( 4098:M 4087:9 4084:X 4062:c 4058:c 4052:b 4049:+ 4046:a 4040:: 4035:b 4031:b 4025:a 4022:+ 4019:c 4013:: 4008:a 4004:a 3998:c 3995:+ 3992:b 3976:a 3972:N 3961:8 3958:X 3935:c 3929:b 3926:+ 3923:a 3918:b 3915:a 3909:: 3903:b 3897:a 3894:+ 3891:c 3886:a 3883:c 3877:: 3871:a 3865:c 3862:+ 3859:b 3854:c 3851:b 3835:e 3831:G 3820:7 3817:X 3797:c 3794:: 3791:b 3788:: 3785:a 3773:K 3762:6 3759:X 3739:) 3736:B 3730:A 3727:( 3718:: 3715:) 3712:A 3706:C 3703:( 3694:: 3691:) 3688:C 3682:B 3679:( 3661:N 3650:5 3647:X 3623:C 3614:: 3611:B 3602:: 3599:A 3581:H 3570:4 3567:X 3539:C 3530:: 3527:B 3518:: 3515:A 3497:O 3486:3 3483:X 3451:b 3448:a 3445:: 3442:a 3439:c 3436:: 3433:c 3430:b 3418:G 3407:2 3404:X 3376:1 3373:: 3370:1 3367:: 3364:1 3352:I 3341:1 3338:X 3290:b 3287:a 3279:: 3271:a 3268:c 3260:: 3252:c 3249:b 3224:a 3221:b 3213:: 3205:c 3202:a 3194:: 3186:b 3183:c 3147:f 3123:3 3119:/ 3112:2 3106:C 3103:, 3100:B 3097:, 3094:A 3076:) 3071:3 3063:+ 3060:A 3057:( 3040:3 3036:/ 3029:2 3023:C 3013:3 3009:/ 3002:2 2996:B 2969:2 2965:b 2961:+ 2958:b 2955:a 2952:+ 2947:2 2943:a 2934:2 2930:c 2917:2 2913:a 2909:+ 2906:a 2903:c 2900:+ 2895:2 2891:c 2882:2 2878:b 2860:0 2853:3 2849:/ 2842:2 2836:A 2819:2 2815:c 2811:+ 2808:c 2805:b 2802:+ 2797:2 2793:b 2784:2 2780:a 2768:1 2762:{ 2757:= 2754:) 2751:c 2748:, 2745:b 2742:, 2739:a 2736:( 2733:f 2696:. 2692:) 2686:3 2678:+ 2675:C 2671:( 2661:: 2657:) 2651:3 2643:+ 2640:B 2636:( 2626:: 2622:) 2616:3 2608:+ 2605:A 2601:( 2575:△ 2568:△ 2561:△ 2542:△ 2530:f 2512:) 2509:c 2506:, 2503:b 2500:, 2497:a 2494:( 2491:f 2488:= 2478:) 2473:2 2469:a 2460:2 2456:c 2452:+ 2447:2 2443:b 2439:( 2436:a 2433:= 2423:) 2418:2 2414:a 2405:2 2401:b 2397:+ 2392:2 2388:c 2384:( 2381:a 2378:= 2371:) 2368:b 2365:, 2362:c 2359:, 2356:a 2353:( 2350:f 2322:) 2319:c 2316:, 2313:b 2310:, 2307:a 2304:( 2301:f 2296:3 2292:t 2288:= 2276:] 2271:) 2266:2 2262:a 2253:2 2249:c 2245:+ 2240:2 2236:b 2232:( 2229:a 2224:[ 2217:3 2213:t 2209:= 2197:] 2190:2 2186:) 2182:a 2179:t 2176:( 2168:2 2164:) 2160:c 2157:t 2154:( 2151:+ 2146:2 2142:) 2138:b 2135:t 2132:( 2127:[ 2122:a 2119:t 2116:= 2109:) 2106:c 2103:t 2100:, 2097:b 2094:t 2091:, 2088:a 2085:t 2082:( 2079:f 2065:f 2050:) 2044:2 2040:a 2031:2 2027:c 2023:+ 2018:2 2014:b 2009:( 2005:a 2002:= 1998:) 1994:c 1991:, 1988:b 1985:, 1982:a 1978:( 1974:f 1952:. 1949:) 1944:2 1940:c 1931:2 1927:b 1923:+ 1918:2 1914:a 1910:( 1907:c 1904:: 1901:) 1896:2 1892:b 1883:2 1879:a 1875:+ 1870:2 1866:c 1862:( 1859:b 1856:: 1853:) 1848:2 1844:a 1835:2 1831:c 1827:+ 1822:2 1818:b 1814:( 1811:a 1796:△ 1775:) 1773:t 1769:t 1765:t 1763:( 1758:c 1754:b 1750:a 1744:b 1740:a 1734:a 1730:c 1724:c 1720:b 1714:D 1708:T 1704:D 1690:. 1687:T 1681:b 1677:a 1671:a 1667:c 1661:c 1657:b 1647:T 1627:. 1622:2 1618:b 1614:+ 1611:b 1608:a 1605:+ 1600:2 1596:a 1587:2 1583:c 1578:; 1573:2 1569:a 1565:+ 1562:a 1559:c 1556:+ 1551:2 1547:c 1538:2 1534:b 1529:; 1524:2 1520:c 1516:+ 1513:c 1510:b 1507:+ 1502:2 1498:b 1489:2 1485:a 1466:X 1450:. 1445:2 1441:b 1437:+ 1432:2 1428:a 1419:2 1415:c 1410:, 1405:2 1401:a 1397:+ 1392:2 1388:c 1379:2 1375:b 1370:, 1365:2 1361:c 1357:+ 1352:2 1348:b 1339:2 1335:a 1323:T 1311:X 1304:X 1297:X 1293:4 1290:X 1286:3 1283:X 1272:T 1258:T 1243:. 1240:b 1237:+ 1234:a 1228:c 1224:, 1221:a 1218:+ 1215:c 1209:b 1205:, 1202:c 1199:+ 1196:b 1190:a 1166:3 1161:R 1123:2 1119:/ 1115:1 1111:c 1107:: 1102:2 1098:/ 1094:1 1090:b 1086:: 1081:2 1077:/ 1073:1 1069:a 1051:X 1035:. 1030:3 1025:R 988:c 985:a 955:b 952:a 927:) 924:c 921:, 918:b 915:, 912:a 909:( 906:f 879:c 876:b 873:= 870:) 867:c 864:, 861:b 858:, 855:a 852:( 847:2 843:f 819:a 816:1 810:= 807:) 804:c 801:, 798:b 795:, 792:a 789:( 784:1 780:f 736:) 733:b 730:, 727:a 724:, 721:c 718:( 715:f 712:: 709:) 706:a 703:, 700:c 697:, 694:b 691:( 688:f 685:: 682:) 679:c 676:, 673:b 670:, 667:a 664:( 661:f 643:f 639:f 622:. 619:) 616:b 613:, 610:c 607:, 604:a 601:( 598:f 595:= 592:) 589:c 586:, 583:b 580:, 577:a 574:( 571:f 560:. 556:t 551:n 537:) 534:c 531:, 528:b 525:, 522:a 519:( 516:f 511:n 507:t 503:= 500:) 497:c 494:t 491:, 488:b 485:t 482:, 479:a 476:t 473:( 470:f 452:f 425:2 421:X 400:) 397:2 394:( 391:X 367:n 345:n 341:X 320:) 317:n 314:( 311:X 155:) 153:e 142:N 127:) 125:H 110:) 108:O 92:) 90:G 75:) 73:I 50:△ 34:. 20:)

Index

Triangle center function
Triangle Center

Angle bisectors
incircle
incenter
Medians
centroid
Perpendicular bisectors
circumcircle
Altitudes
orthocenter
Nine-point circle
nine-point center
Euler line
geometry
point
triangle
plane
centroid
circumcenter
incenter
orthocenter
ancient Greeks
constructions
invariant
equivariant
similarity transformations
rotation
reflection

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