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Tangent lines to circles

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7633:, which is to calculate the length of a belt or rope needed to fit snugly over two pulleys. If the belt is considered to be a mathematical line of negligible thickness, and if both pulleys are assumed to lie in exactly the same plane, the problem devolves to summing the lengths of the relevant tangent line segments with the lengths of circular arcs subtended by the belt. If the belt is wrapped about the wheels so as to cross, the interior tangent line segments are relevant. Conversely, if the belt is wrapped exteriorly around the pulleys, the exterior tangent line segments are relevant; this case is sometimes called the 4283:, whereas the internal tangent lines intersect at the internal homothetic center. Both the external and internal homothetic centers lie on the line of centers (the line connecting the centers of the two circles), closer to the center of the smaller circle: the internal center is in the segment between the two circles, while the external center is not between the points, but rather outside, on the side of the center of the smaller circle. If the two circles have equal radius, there are still four bitangents, but the external tangent lines are parallel and there is no external center in the 4256: 4304: 235: 160: 5170: 4895: 2197: 1536: 1479: 5292: 7788: 5050: 3800: 7153: 6747: 4052: 4885: 1041: 4628: 1018: 6813: 3222: 7746: 7599:
but considered "inside out"), in which case if the radii have opposite sign (one circle has negative radius and the other has positive radius) the external and internal homothetic centers and external and internal bitangents are switched, while if the radii have the same sign (both positive radii or
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A third generalization considers tangent circles, rather than tangent lines; a tangent line can be considered as a tangent circle of infinite radius. In particular, the external tangent lines to two circles are limiting cases of a family of circles which are internally or externally tangent to both
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Two distinct circles may have between zero and four bitangent lines, depending on configuration; these can be classified in terms of the distance between the centers and the radii. If counted with multiplicity (counting a common tangent twice) there are zero, two, or four bitangent lines. Bitangent
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Geometrically this corresponds to computing the angle formed by the tangent lines and the line of centers, and then using that to rotate the equation for the line of centers to yield an equation for the tangent line. The angle is computed by computing the trigonometric functions of a right triangle
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there may be any number between zero and four bitangent lines; these are addressed below. For two of these, the external tangent lines, the circles fall on the same side of the line; for the two others, the internal tangent lines, the circles fall on opposite sides of the line. The external tangent
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Animation showing the inversive transformation of an Apollonius problem. The blue and red circles swell to tangency, and are inverted in the grey circle, producing two straight lines. The yellow solutions are found by sliding a circle between them until it touches the transformed green circle from
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Note that in these degenerate cases the external and internal homothetic center do generally still exist (the external center is at infinity if the radii are equal), except if the circles coincide, in which case the external center is not defined, or if both circles have radius zero, in which case
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The bitangent lines can be constructed either by constructing the homothetic centers, as described at that article, and then constructing the tangent lines through the homothetic center that is tangent to one circle, by one of the methods described above. The resulting line will then be tangent to
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Bitangent lines can also be defined when one or both of the circles has radius zero. In this case the circle with radius zero is a double point, and thus any line passing through it intersects the point with multiplicity two, hence is "tangent". If one circle has radius zero, a bitangent line is
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problem). To solve this problem, the center of any such circle must lie on an angle bisector of any pair of the lines; there are two angle-bisecting lines for every intersection of two lines. The intersections of these angle bisectors give the centers of solution circles. There are four such
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in their tangent point with respect to a circle of appropriate radius transforms the two touching given circles into two parallel lines, and the third given circle into another circle. Thus, the solutions may be found by sliding a circle of constant radius between two parallel lines until it
4229: 7324:) – have one point of external tangency – then they have two external bitangents and one internal bitangent, namely the common tangent line. This common tangent line has multiplicity two, as it separates the circles (one on the left, one on the right) for either orientation (direction). 2653: 6414: 2478: 2975: 4428: 151:
The radius of a circle is perpendicular to the tangent line through its endpoint on the circle's circumference. Conversely, the perpendicular to a radius through the same endpoint is a tangent line. The resulting geometrical figure of circle and tangent line has a
782: 1474:{\displaystyle {\begin{aligned}y&=-{\frac {x_{1}-a}{y_{1}-b}}x+y_{1}+x_{1}{\frac {x_{1}-a}{y_{1}-b}}\\y-y_{1}&=(x_{1}-x){\frac {x_{1}-a}{y_{1}-b}}\\(y-y_{1})(y_{1}-b)&=-(x-x_{1})(x_{1}-a)\\(x-x_{1})(x_{1}-a)+(y-y_{1})(y_{1}-b)&=0\end{aligned}}} 2989: 6625: 5697: 6133: 4059: 7604:
simply a line tangent to the circle and passing through the point, and is counted with multiplicity two. If both circles have radius zero, then the bitangent line is the line they define, and is counted with multiplicity four.
3795: 2483: 7148:{\displaystyle {\begin{aligned}(t_{2}-v_{2})\cdot (t_{2}-t_{1})&=0\\(t_{1}-v_{1})\cdot (t_{2}-t_{1})&=0\\(t_{1}-v_{1})\cdot (t_{1}-v_{1})&=r_{1}^{2}\\(t_{2}-v_{2})\cdot (t_{2}-v_{2})&=r_{2}^{2}\\\end{aligned}}} 6226: 6417:
whose vertices are the (external) homothetic center, a center of a circle, and a tangent point; the hypotenuse lies on the tangent line, the radius is opposite the angle, and the adjacent side lies on the line of centers.
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can also be understood in terms of limits of other configurations – e.g., a limit of two circles that almost touch, and moving one so that they touch, or a circle with small radius shrinking to a circle of zero radius.
2331: 4047:{\displaystyle {\begin{aligned}{\overline {BP}}={\overline {BQ}}=b,&\quad {\overline {CQ}}={\overline {CR}}=c,\\{\overline {DR}}={\overline {DS}}=d,&\quad {\overline {AS}}={\overline {AP}}=a.\end{aligned}}} 1046: 4880:{\displaystyle {\begin{aligned}\gamma &=-{\text{atan2}}\left({y_{2}-y_{1}},{x_{2}-x_{1}}\right)\\\beta &=\pm \arcsin \left({\frac {R-r}{\sqrt {(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}}}}\right)\end{aligned}}} 787: 5858: 4666: 3450: 2799: 5773: 573: 6027: 7990: 6818: 6243: 6143: 5574: 4433: 4064: 3859: 7527:) then they have no bitangents, as a tangent line to the outer circle does not intersect the inner circle, or conversely a tangent line to the inner circle is a secant line to the outer circle. 771: 7407: 5070:
these constructions break down; to simplify exposition this is not discussed in this section, but a form of the construction can work in limit cases (e.g., two circles tangent at one point).
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The concept of a tangent line to one or more circles can be generalized in several ways. First, the conjugate relationship between tangent points and tangent lines can be generalized to
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at the desired tangent points. The desired internal tangent lines are the lines perpendicular to these radial lines at those tangent points, which may be constructed as described above.
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at the desired tangent points. The desired external tangent lines are the lines perpendicular to these radial lines at those tangent points, which may be constructed as described above.
4623:{\displaystyle {\begin{aligned}x_{3}&=x_{1}\pm r\sin \alpha \\y_{3}&=y_{1}\pm r\cos \alpha \\x_{4}&=x_{2}\pm R\sin \alpha \\y_{4}&=y_{2}\pm R\cos \alpha \\\end{aligned}}} 6050: 659: 4980: 427: 8129: 7860:
which maps one to the other. In Möbius geometry, tangency between a line and a circle becomes a special case of tangency between two circles. This equivalence is extended further in
7597: 6509: 2090: 1013:{\displaystyle {\begin{aligned}{\overset {}{(}}x-a)^{2}+(y-b)^{2}&=r^{2}\\2(x-a)+2(y-b){\frac {dy}{dx}}&=0\\{\frac {dy}{dx}}&=-{\frac {x_{1}-a}{y_{1}-b}}\end{aligned}}} 5956: 5907: 3325: 2326: 2714: 7525: 7468:) – have one point of internal tangency – then they have no internal bitangents and one external bitangent, namely the common tangent line, which has multiplicity two, as above. 1975: 8046: 7845:
circles, while the internal tangent lines are limiting cases of a family of circles which are internally tangent to one and externally tangent to the other of the two circles.
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An inner tangent is a tangent that intersects the segment joining two circles' centers. Note that the inner tangent will not be defined for cases when the two circles overlap.
7269: 2257: 7466: 2146: 5564: 7322: 3638: 2192: 7198: 3502: 2027: 3711: 5515: 3544: 3217:{\displaystyle {\binom {x_{1/2}}{y_{1/2}}}={\frac {r^{2}}{d_{0}^{2}}}{\binom {x_{0}}{y_{0}}}\pm {\frac {r}{d_{0}^{2}}}{\sqrt {d_{0}^{2}-r^{2}}}{\binom {-y_{0}}{x_{0}}}.} 3592: 6138: 1919: 7531:
Finally, if the two circles are identical, any tangent to the circle is a common tangent and hence (external) bitangent, so there is a circle's worth of bitangents.
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A general Apollonius problem can be transformed into the simpler problem of circle tangent to one circle and two parallel lines (itself a special case of the
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intersect a circle at two points, whereas another line may not intersect a circle at all. This property of tangent lines is preserved under many geometrical
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involve finding a circle that is tangent to one or more lines. The simplest of these is to construct circles that are tangent to three given lines (the
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that are tangent to this new circle. These lines are parallel to the desired tangent lines, because the situation corresponds to shrinking both circles
4224:{\displaystyle {\begin{aligned}&{\overline {AB}}+{\overline {CD}}=(a+b)+(c+d)\\={}&{\overline {BC}}+{\overline {DA}}=(b+c)+(d+a)\end{aligned}}} 7409:), then they have no internal bitangents and two external bitangents (they cannot be separated, because they intersect, hence no internal bitangents). 5778: 3807:
This conclusion follows from the equality of the tangent segments from the four vertices of the quadrilateral. Let the tangent points be denoted as
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both negative radii) "external" and "internal" have the same usual sense (switching one sign switches them, so switching both switches them back).
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This theorem and its converse have various uses. For example, they show immediately that no rectangle can have an inscribed circle unless it is a
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outside of the circle. The geometrical figure of a circle and both tangent lines likewise has a reflection symmetry about the radial axis joining
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the other circle as well. Alternatively, the tangent lines and tangent points can be constructed more directly, as detailed below. Note that in
1697: 1551: 1489: 55: 5718: 2648:{\displaystyle {\binom {a}{b_{\pm }}}={\frac {r^{2}}{x_{0}}}{\binom {1}{0}}\pm {\frac {r}{x_{0}}}{\sqrt {x_{0}^{2}-r^{2}}}{\binom {0}{1}}\ .} 464: 5342:
that are tangent to this new circle. These lines are parallel to the desired tangent lines, because the situation corresponds to shrinking
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The converse is also true: a circle can be inscribed into every quadrilateral in which the lengths of opposite sides sum to the same value.
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Now that we have the slope of the tangent line, we can substitute the slope and the coordinate of the tangency point into the line equation
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circles in general, the inscribed circle of the triangle formed by the intersection of the three lines, and the three exscribed circles.
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be the six intersection points, with the same letter corresponding to the same line and the index 1 corresponding to the point closer to
7829:, in which the pole points may be anywhere, not only on the circumference of the circle. Second, the union of two circles is a special ( 6721:
to the right, and the two tangent lines will cross. In this way all four solutions are obtained. Switching signs of both radii switches
6409:{\displaystyle {\begin{aligned}a&=RX-kY{\sqrt {1-R^{2}}}\\b&=RY+kX{\sqrt {1-R^{2}}}\\c&=r_{1}-(ax_{1}+by_{1})\end{aligned}}} 7203:
These are four quadratic equations in two two-dimensional vector variables, and in general position will have four pairs of solutions.
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is defined as the larger of the two circles. Two different methods may be used to construct the external and internal tangent lines.
2473:{\displaystyle a={\frac {r^{2}}{x_{0}}},\qquad b_{\pm }=\pm {\sqrt {r^{2}-a^{2}}}=\pm {\frac {r}{x_{0}}}{\sqrt {x_{0}^{2}-r^{2}}}.} 2970:{\textstyle {\vec {e}}_{1}={\frac {1}{d_{0}}}{\binom {x_{0}}{y_{0}}},\ {\vec {e}}_{2}={\frac {1}{d_{0}}}{\binom {-y_{0}}{x_{0}}}.} 3345: 4931: 5964: 7923: 5912: 5863: 682: 7330: 2732: 7779:
contacts the transformed third circle. Re-inversion produces the corresponding solutions to the original problem.
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showed in the early 19th century that these six points lie on four lines, each line having three collinear points.
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Further, the notion of bitangent lines can be extended to circles with negative radius (the same locus of points,
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No tangent line can be drawn through a point within a circle, since any such line must be a secant line. However,
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of any number of sides; in addition, for every number of polygon sides there are an infinite number of non-
2036: 7745: 3268: 2271: 212: 133: 109: 2660: 1667:, respectively. But only a tangent line is perpendicular to the radial line. Hence, the two lines from 7868: 7856:, lines are viewed as circles through a point "at infinity" and for any line and any circle, there is a 7755: 7474: 3668: 1924: 349: 8012: 7228: 6620:{\displaystyle {\begin{pmatrix}R&\mp {\sqrt {1-R^{2}}}\\\pm {\sqrt {1-R^{2}}}&R\end{pmatrix}}} 5692:{\displaystyle {\begin{aligned}ax_{1}+by_{1}+c&=r_{1}\\ax_{2}+by_{2}+c&=r_{2}\\\end{aligned}}} 4255: 2207: 8061: 7415: 2099: 5520: 8165: 7861: 7834: 7830: 7281: 6128:{\displaystyle X={\frac {\Delta x}{d}},\quad Y={\frac {\Delta y}{d}},\quad R={\frac {\Delta r}{d}}} 3597: 2151: 300: 153: 145: 7160: 3464: 1984: 8252: 7853: 7820: 7808: 7775: 7771: 3648: 137: 125: 59: 31: 7849: 7646: 5473: 4303: 3507: 1547: 3558: 8292: 8273: 8210: 7724: 4921: 4292: 4280: 4260: 4240: 578: 1886: 50:, never entering the circle's interior. Tangent lines to circles form the subject of several 8319: 8244: 7272: 7200:
is perpendicular to the radii, and that the tangent points lie on their respective circles.
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depending upon the need to find distances from the centers of the nearer or farther circle,
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have a conjugate relationship to one another, which has been generalized into the idea of
234: 141: 39: 1645:; since both are inscribed in a semicircle, they are perpendicular to the line segments 8276: 8151: 7872: 7826: 7816: 3550: 255: 5053:
Inner tangent. The external tangent lines pass through the internal homothetic center.
8313: 8256: 7728: 4244: 3703: 1524: 90: 78: 3790:{\displaystyle {\overline {AB}}+{\overline {CD}}={\overline {BC}}+{\overline {DA}}.} 8229: 8215: 7791:
The concept of a tangent line and tangent point can be generalized to a pole point
7629: 7622: 6515:, equivalently the direction of rotation), and the above equations are rotation of 4270:
For two circles, there are generally four distinct lines that are tangent to both (
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Construction of a tangent to a given circle (black) from a given exterior point (
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of the tangent line and circle, even though the line and circle may be deformed.
6221:{\displaystyle {\begin{aligned}aX+bY&=R,\\a^{2}+b^{2}&=1;\end{aligned}}} 5169: 4894: 2196: 1535: 227:
to any two intersection points of the circle with a secant line passing through
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two of the three given circles until they just touch, i.e., are tangent. An
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is a closed figure of four straight sides that are tangent to a given circle
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BSHM Bulletin: Journal of the British Society for the History of Mathematics
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But each side of the quadrilateral is composed of two such tangent segments
8146: 7875:. The parametric representation of the unit hyperbola via radius vector is 7212:
lines can also be generalized to circles with negative or zero radius. The
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outside the circle and the secant line joining its two points of tangency.
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to simplify equation (1), resulting in the following system of equations:
7723:). Since each pair of circles has two homothetic centers, there are six 4920:
and the point where the two outer tangents of the two circles intersect (
3660: 3656: 129: 3706:, the sums of opposite sides of any such quadrilateral are equal, i.e., 3652: 63: 51: 7867:
Radius and tangent line are perpendicular at a point of a circle, and
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The distances between the centers of the nearer and farther circles,
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between a chord and a tangent is half the arc belonging to the chord.
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These equations express that the tangent line, which is parallel to
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and the new circle are the tangent points for lines passing through
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to this quartic curve. A generic quartic curve has 28 bitangents.
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The internal and external tangent lines are useful in solving the
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each of whose sides is tangent to a particular circle, called its
2195: 1534: 233: 158: 144:. In technical language, these transformations do not change the 5853:{\displaystyle \Delta x=x_{2}-x_{1},\quad \Delta y=y_{2}-y_{1}} 3265:
lies on the circle and there is just one tangent with equation
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A circle is drawn centered on the midpoint of the line segment
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to that point, theorems involving tangent lines often involve
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is the tangent line to the right of the circles looking from
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is the tangent line to the right of the circles looking from
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is the angle between the line of centers and a tangent line.
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Euclidean and Transformational Geometry: A Deductive Inquiry
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to a point. Two radial lines may be drawn from the center
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respectively can be found out using similarity as follows:
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is the outer tangent between the two circles. Given points
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is a normal vector of the line. The tangent intersects the
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We begin by taking the implicit derivative with respect to
3445:{\displaystyle x_{1}x+y_{1}y=r^{2},\ x_{2}x+y_{2}y=r^{2}.} 2796:
and the unit base vectors by the orthogonal unit vectors
8169:"When A Quadrilateral Is Inscriptible?" at Cut-the-knot 6772:
for the four lines tangent to two circles with centers
5768:{\displaystyle a\Delta x+b\Delta y=\Delta r,\qquad (1)} 4274:) – if the two circles are outside each other – but in 3847:). The symmetric tangent segments about each point of 1712:
Draw any three different lines through the given point
568:{\displaystyle (x-x_{1})(x_{1}-a)+(y-y_{1})(y_{1}-b)=0} 258:. The same reciprocal relation exists between a point 8097: 8017: 7928: 7837:, and the external and internal tangent lines are the 6685:
The above assumes each circle has positive radius. If
6546: 6022:{\textstyle d={\sqrt {(\Delta x)^{2}+(\Delta y)^{2}}}} 5967: 2802: 2735: 207:
of the circle. Thus the lengths of the segments from
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The radius and tangent are hyperbolic orthogonal at
7985:{\displaystyle {\tfrac {dp}{da}}=(\sinh a,\cosh a).} 5333:. Using the method above, two lines are drawn from 5211:. Using the method above, two lines are drawn from 195:
tangent lines can be drawn to a circle from a point
7770:special case). To accomplish this, it suffices to 4644:can be computed using basic trigonometry. You have 4307:
Finding outer tangent. Two circles' outer tangents.
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Tangent quadrilateral theorem and inscribed circles
581:of the circle. Say that the circle has equation of 223:. This power equals the product of distances from 8147:"Finding tangents to a circle with a straightedge" 8123: 8040: 7984: 7591: 7519: 7460: 7401: 7316: 7263: 7192: 7147: 6619: 6503: 6408: 6220: 6127: 6021: 5950: 5901: 5852: 5767: 5691: 5558: 5509: 4974: 4879: 4640:notate the radii of the two circles and the angle 4622: 4223: 4046: 3789: 3632: 3586: 3538: 3496: 3444: 3319: 3216: 2969: 2788: 2708: 2647: 2472: 2320: 2251: 2186: 2140: 2084: 2021: 1969: 1913: 1473: 1012: 766:{\displaystyle (x_{1}-a)^{2}+(y_{1}-b)^{2}=r^{2}.} 765: 653: 567: 421: 8230:"The tangency problem of Apollonius: three looks" 7402:{\displaystyle |r_{1}-r_{2}|<d<r_{1}+r_{2}} 6808:are given by solving the simultaneous equations: 5369:. Two radial lines may be drawn from the center 3205: 3173: 3107: 3080: 3039: 2996: 2633: 2620: 2559: 2546: 2510: 2490: 54:, and play an important role in many geometrical 5715:by subtracting the first from the second yields 5470:respectively. Expressing a line by the equation 4419:can easily be calculated with help of the angle 2789:{\textstyle d_{0}={\sqrt {x_{0}^{2}+y_{0}^{2}}}} 661:and we are finding the slope of tangent line at 27:Line which touches a circle at exactly one point 8050:are reflections of each other in the asymptote 7641:Tangent lines to three circles: Monge's theorem 215:, the square of this tangent length equals the 187:, the length of the tangent line segment (red). 7471:If one circle is completely inside the other ( 7412:If the circles touch internally at one point ( 4291:, the external homothetic center lies at the 2958: 2926: 2872: 2845: 211:to the two tangent points are equal. By the 8: 8060:of the unit hyperbola. When interpreted as 7909:points in the direction of tangent line at 4295:corresponding to the slope of these lines. 348:Suppose that the equation of the circle in 4259:The external (above) and internal (below) 1855:This line meets the circle at two points, 654:{\displaystyle (x-a)^{2}+(y-b)^{2}=r^{2},} 8096: 8076: 8016: 8014: 7927: 7925: 7811:of each other with respect to the circle. 7580: 7558: 7545: 7539: 7512: 7506: 7493: 7484: 7476: 7453: 7447: 7434: 7425: 7417: 7393: 7380: 7362: 7356: 7343: 7334: 7332: 7308: 7295: 7283: 7255: 7242: 7230: 7181: 7168: 7162: 7135: 7130: 7110: 7097: 7078: 7065: 7048: 7043: 7023: 7010: 6991: 6978: 6948: 6935: 6916: 6903: 6873: 6860: 6841: 6828: 6817: 6815: 6596: 6584: 6569: 6557: 6541: 6539: 6493: 6481: 6476: 6393: 6377: 6358: 6332: 6320: 6283: 6271: 6242: 6240: 6195: 6182: 6142: 6140: 6110: 6085: 6060: 6052: 6011: 5989: 5974: 5966: 5942: 5929: 5914: 5893: 5880: 5865: 5844: 5831: 5808: 5795: 5780: 5720: 5679: 5656: 5640: 5623: 5600: 5584: 5573: 5571: 5541: 5528: 5522: 5475: 4975:{\displaystyle {\frac {dr}{r_{1}-r_{2}}}} 4963: 4950: 4935: 4933: 4860: 4850: 4837: 4821: 4811: 4798: 4777: 4738: 4725: 4720: 4710: 4697: 4692: 4682: 4665: 4663: 4595: 4578: 4549: 4532: 4503: 4486: 4457: 4440: 4432: 4430: 4166: 4148: 4144: 4086: 4068: 4063: 4061: 4016: 3998: 3971: 3953: 3925: 3907: 3880: 3862: 3858: 3856: 3769: 3751: 3733: 3715: 3713: 3621: 3608: 3599: 3569: 3560: 3518: 3509: 3488: 3475: 3466: 3433: 3417: 3401: 3385: 3369: 3353: 3347: 3308: 3292: 3276: 3270: 3204: 3197: 3186: 3172: 3170: 3162: 3149: 3144: 3138: 3130: 3125: 3116: 3106: 3099: 3089: 3079: 3077: 3069: 3064: 3054: 3048: 3038: 3027: 3023: 3009: 3005: 2995: 2993: 2991: 2957: 2950: 2939: 2925: 2923: 2915: 2906: 2897: 2886: 2885: 2871: 2864: 2854: 2844: 2842: 2834: 2825: 2816: 2805: 2804: 2801: 2778: 2773: 2760: 2755: 2749: 2740: 2734: 2697: 2684: 2668: 2662: 2632: 2619: 2617: 2609: 2596: 2591: 2585: 2577: 2568: 2558: 2545: 2543: 2535: 2525: 2519: 2509: 2502: 2489: 2487: 2485: 2459: 2446: 2441: 2435: 2427: 2418: 2404: 2391: 2385: 2373: 2357: 2347: 2341: 2333: 2309: 2283: 2279: 2273: 2231: 2215: 2209: 2175: 2162: 2153: 2123: 2107: 2101: 2076: 2041: 2040: 2038: 2010: 1986: 1958: 1945: 1932: 1926: 1888: 1442: 1426: 1395: 1379: 1347: 1331: 1293: 1277: 1245: 1227: 1220: 1205: 1185: 1156: 1138: 1131: 1125: 1112: 1087: 1069: 1062: 1045: 1043: 991: 973: 966: 936: 902: 853: 836: 811: 790: 786: 784: 754: 741: 725: 709: 693: 684: 642: 629: 604: 586: 544: 528: 497: 481: 466: 441:. Then the tangent line of the circle at 422:{\displaystyle (x-a)^{2}+(y-b)^{2}=r^{2}} 413: 400: 375: 357: 8124:{\displaystyle jp(a)={\tfrac {dp}{da}}.} 7327:If the circles intersect in two points ( 3504:describes the circle inversion of point 8138: 7278:If they touch externally at one point ( 7225:If the circles are outside each other ( 6750:Finding outer tangent. Circle tangents. 2720:-axis: In the vector form one replaces 1921:be a point of the circle with equation 6712:will lie to the left of each line and 6235:) for the two external tangent lines: 1484:Compass and straightedge constructions 7592:{\displaystyle x^{2}+y^{2}=(-r)^{2},} 6504:{\displaystyle \pm {\sqrt {1-R^{2}}}} 5067: 4275: 3663:is a tangential polygon, as is every 2204:Conversely, if one starts with point 2085:{\displaystyle {\vec {OP}}=(a,b)^{T}} 7: 7741:Special cases of Apollonius' problem 7678:, there are three pairs of circles ( 7608:the internal center is not defined. 5951:{\displaystyle \Delta r=r_{2}+r_{1}} 5902:{\displaystyle \Delta r=r_{2}-r_{1}} 5041:between the centers of two circles. 3342:there are 2 tangents with equations 3320:{\displaystyle x_{0}x+y_{0}y=r^{2}.} 2321:{\displaystyle P_{1/2}=(a,b_{\pm })} 1704:external to the circle using only a 1500:on the circumference of the circle: 1488:It is relatively straightforward to 269:is exterior to a circle with center 5096:be the centers of the two circles, 2709:{\displaystyle P_{0}=(x_{0},y_{0})} 7520:{\displaystyle d<|r_{1}-r_{2}|} 6754:In general the points of tangency 6228:solve these to get two solutions ( 6113: 6088: 6063: 6001: 5979: 5916: 5867: 5818: 5782: 5746: 5737: 5725: 3177: 3084: 3000: 2930: 2849: 2624: 2550: 2494: 2268:meet the circle at the two points 1970:{\displaystyle x^{2}+y^{2}=r^{2}.} 1582:is again the center of the circle 25: 8041:{\displaystyle {\tfrac {dp}{da}}} 7795:and its corresponding polar line 6431:is the unit vector pointing from 5566:then a bitangent line satisfies: 5295:Construction of the inner tangent 5173:Construction of the outer tangent 577:This can be proved by taking the 313:is drawn from the tangency point 7264:{\displaystyle d>r_{1}+r_{2}} 4311:The red line joining the points 4279:lines intersect in the external 2986:touch the circle at the points 2977:Then the tangents through point 2252:{\displaystyle P_{0}=(x_{0},0),} 1716:that intersect the circle twice. 273:, and if the tangent lines from 7461:{\displaystyle d=|r_{1}-r_{2}|} 6103: 6078: 5817: 5755: 3997: 3906: 2368: 2141:{\displaystyle P_{0}=(x_{0},0)} 1496:tangent to a circle at a point 8296:"Tangent lines to two circles" 8090: 8084: 7976: 7952: 7577: 7567: 7513: 7485: 7454: 7426: 7363: 7335: 7116: 7090: 7084: 7058: 7029: 7003: 6997: 6971: 6954: 6928: 6922: 6896: 6879: 6853: 6847: 6821: 6399: 6367: 6008: 5998: 5986: 5976: 5762: 5756: 5559:{\displaystyle a^{2}+b^{2}=1,} 5378:through the tangent points on 5265:through the tangent points on 4857: 4830: 4818: 4791: 4214: 4202: 4196: 4184: 4134: 4122: 4116: 4104: 3581: 3562: 3530: 3511: 2891: 2810: 2703: 2677: 2315: 2296: 2259:than the two tangents through 2243: 2224: 2135: 2116: 2073: 2060: 2051: 1908: 1896: 1454: 1435: 1432: 1413: 1407: 1388: 1385: 1366: 1359: 1340: 1337: 1318: 1305: 1286: 1283: 1264: 1217: 1198: 899: 887: 878: 866: 833: 820: 808: 792: 738: 718: 706: 686: 626: 613: 601: 588: 556: 537: 534: 515: 509: 490: 487: 468: 397: 384: 372: 359: 156:about the axis of the radius. 1: 8277:"Tangent lines to one circle" 7651:For three circles denoted by 7317:{\displaystyle d=r_{1}+r_{2}} 5404:Let the circles have centres 4898:Outer tangents to two circles 3633:{\displaystyle xx_{0}=r^{2}.} 2187:{\displaystyle ax_{0}=r^{2}.} 1774:be the point where the lines 1700:the tangent lines to a point 1554:the tangent lines to a point 112:the circle at a single point 7275:, there are four bitangents. 7193:{\displaystyle t_{2}-t_{1},} 4251:Tangent lines to two circles 4176: 4158: 4096: 4078: 4026: 4008: 3981: 3963: 3935: 3917: 3890: 3872: 3779: 3761: 3743: 3725: 3690:. Equivalently, the circle 3497:{\displaystyle ax_{0}=r^{2}} 2033:lies on both the curves and 2022:{\displaystyle ax+by=r^{2},} 1615:, by the following argument. 8071:), the two numbers satisfy 7827:pole points and polar lines 6534:using the rotation matrix: 5351:to a point while expanding 4891:the 2-argument arctangent. 1866:The tangents are the lines 277:touch the circle at points 256:pole points and polar lines 97:Tangent lines to one circle 18:Tangent between two circles 8336: 8202:Libeskind, Shlomo (2007), 7814: 7738: 7644: 7620: 6511:(depending on the sign of 5909:for the outer tangent or 5510:{\displaystyle ax+by+c=0,} 3539:{\displaystyle (x_{0},0).} 1689:are tangent to the circle 8249:10.1080/17498430601148911 5152:; in other words, circle 3587:{\displaystyle (x_{0},0)} 167:, the product of lengths 3803:Tangential quadrilateral 3681:tangential quadrilateral 2480:Written in vector form: 2200:Tangents through a point 1641:are radii of the circle 1589:The intersection points 181:equals to the square of 165:power-of-a-point theorem 36:tangent line to a circle 32:Euclidean plane geometry 7640: 5958:for the inner tangent. 5517:with the normalization 1914:{\displaystyle P=(a,b)} 1558:external to the circle 459:has Cartesian equation 8125: 8042: 7986: 7812: 7754:Many special cases of 7751: 7593: 7521: 7462: 7403: 7318: 7265: 7194: 7149: 6751: 6621: 6505: 6410: 6222: 6129: 6023: 5952: 5903: 5854: 5769: 5693: 5560: 5511: 5360:by a constant amount, 5296: 5238:by a constant amount, 5174: 5054: 4976: 4899: 4881: 4624: 4308: 4267: 4225: 4048: 3804: 3791: 3634: 3588: 3540: 3498: 3446: 3321: 3218: 2971: 2790: 2710: 2649: 2474: 2322: 2253: 2201: 2188: 2142: 2086: 2023: 1971: 1915: 1879:With analytic geometry 1544: 1475: 1014: 767: 655: 569: 423: 250:and the tangent point 243: 213:secant-tangent theorem 188: 8228:Kunkel, Paul (2007), 8126: 8062:split-complex numbers 8043: 7987: 7869:hyperbolic-orthogonal 7858:Möbius transformation 7790: 7748: 7735:Problem of Apollonius 7594: 7522: 7463: 7404: 7319: 7266: 7195: 7150: 6749: 6622: 6506: 6411: 6223: 6130: 6047:we can normalize by 6029:is the distance from 6024: 5953: 5904: 5855: 5770: 5694: 5561: 5512: 5324:is drawn centered on 5294: 5202:is drawn centered on 5172: 5052: 4977: 4897: 4882: 4625: 4306: 4258: 4233:proving the theorem. 4226: 4049: 3802: 3792: 3698:in the quadrilateral 3671:tangential polygons. 3635: 3589: 3541: 3499: 3447: 3322: 3219: 2972: 2791: 2711: 2650: 2475: 2323: 2254: 2199: 2189: 2143: 2087: 2024: 1972: 1916: 1538: 1476: 1015: 768: 656: 570: 424: 350:Cartesian coordinates 237: 162: 8075: 8013: 7924: 7756:Apollonius's problem 7538: 7475: 7416: 7331: 7282: 7229: 7161: 6814: 6538: 6475: 6239: 6139: 6051: 5965: 5913: 5864: 5779: 5719: 5570: 5521: 5474: 4932: 4662: 4429: 4060: 3855: 3712: 3598: 3559: 3508: 3465: 3346: 3269: 2990: 2800: 2733: 2661: 2484: 2332: 2272: 2208: 2152: 2100: 2037: 1985: 1925: 1887: 1844:Draw a line through 1671:and passing through 1042: 783: 683: 585: 465: 356: 217:power of the point P 203:to the center point 8184:. Whistleralley.com 8166:Alexander Bogomolny 7862:Lie sphere geometry 7835:quartic plane curve 7140: 7053: 4266:of the two circles. 3643:Tangential polygons 3555:The polar of point 3154: 3135: 3074: 2783: 2765: 2601: 2451: 579:implicit derivative 154:reflection symmetry 146:incidence structure 116:. For comparison, 8293:Weisstein, Eric W. 8274:Weisstein, Eric W. 8206:, pp. 110–112 8155:. August 15, 2015. 8121: 8116: 8038: 8036: 7982: 7947: 7871:at a point of the 7854:inversive geometry 7821:Inversive geometry 7813: 7752: 7750:within or without. 7725:homothetic centers 7589: 7517: 7458: 7399: 7314: 7261: 7190: 7145: 7143: 7126: 7039: 6752: 6617: 6611: 6501: 6406: 6404: 6218: 6216: 6125: 6019: 5948: 5899: 5850: 5765: 5689: 5687: 5556: 5507: 5387:; these intersect 5297: 5274:; these intersect 5175: 5074:Synthetic geometry 5055: 4972: 4900: 4877: 4875: 4620: 4618: 4309: 4268: 4221: 4219: 4044: 4042: 3805: 3787: 3649:tangential polygon 3630: 3584: 3536: 3494: 3442: 3317: 3240:no tangents exist. 3214: 3140: 3121: 3060: 2967: 2786: 2769: 2751: 2706: 2645: 2587: 2470: 2437: 2318: 2249: 2202: 2184: 2138: 2082: 2019: 1967: 1911: 1696:Another method to 1619:The line segments 1572:, having diameter 1545: 1471: 1469: 1010: 1008: 763: 651: 565: 419: 344:Cartesian equation 317:of exterior point 244: 189: 8182:"Tangent circles" 8115: 8035: 7946: 6602: 6575: 6499: 6338: 6289: 6123: 6098: 6073: 6017: 5400:Analytic geometry 5287:Internal tangents 5165:External tangents 4970: 4922:homothetic center 4867: 4866: 4685: 4293:point at infinity 4281:homothetic center 4261:homothetic center 4179: 4161: 4099: 4081: 4029: 4011: 3984: 3966: 3938: 3920: 3893: 3875: 3782: 3764: 3746: 3728: 3396: 3203: 3168: 3136: 3105: 3075: 3037: 2956: 2921: 2894: 2883: 2870: 2840: 2813: 2784: 2641: 2631: 2615: 2583: 2557: 2541: 2508: 2465: 2433: 2410: 2363: 2054: 1258: 1169: 1100: 1004: 954: 920: 796: 795: 246:The tangent line 42:that touches the 16:(Redirected from 8327: 8306: 8305: 8287: 8286: 8260: 8259: 8234: 8225: 8219: 8207: 8199: 8193: 8192: 8190: 8189: 8177: 8171: 8163: 8157: 8156: 8143: 8130: 8128: 8127: 8122: 8117: 8114: 8106: 8098: 8070: 8059: 8049: 8047: 8045: 8044: 8039: 8037: 8034: 8026: 8018: 8006: 7995: 7991: 7989: 7988: 7983: 7948: 7945: 7937: 7929: 7919: 7908: 7893: 7806: 7802: 7798: 7794: 7722: 7707: 7692: 7677: 7668: 7659: 7598: 7596: 7595: 7590: 7585: 7584: 7563: 7562: 7550: 7549: 7526: 7524: 7523: 7518: 7516: 7511: 7510: 7498: 7497: 7488: 7467: 7465: 7464: 7459: 7457: 7452: 7451: 7439: 7438: 7429: 7408: 7406: 7405: 7400: 7398: 7397: 7385: 7384: 7366: 7361: 7360: 7348: 7347: 7338: 7323: 7321: 7320: 7315: 7313: 7312: 7300: 7299: 7273:general position 7270: 7268: 7267: 7262: 7260: 7259: 7247: 7246: 7214:degenerate cases 7207:Degenerate cases 7199: 7197: 7196: 7191: 7186: 7185: 7173: 7172: 7154: 7152: 7151: 7146: 7144: 7139: 7134: 7115: 7114: 7102: 7101: 7083: 7082: 7070: 7069: 7052: 7047: 7028: 7027: 7015: 7014: 6996: 6995: 6983: 6982: 6953: 6952: 6940: 6939: 6921: 6920: 6908: 6907: 6878: 6877: 6865: 6864: 6846: 6845: 6833: 6832: 6807: 6798: 6789: 6780: 6771: 6762: 6734: 6727: 6720: 6711: 6702: 6694:is positive and 6693: 6680: 6671: 6662: 6653: 6644: 6635: 6626: 6624: 6623: 6618: 6616: 6615: 6603: 6601: 6600: 6585: 6576: 6574: 6573: 6558: 6533: 6526: 6514: 6510: 6508: 6507: 6502: 6500: 6498: 6497: 6482: 6470: 6463: 6459: 6452: 6448: 6439: 6430: 6415: 6413: 6412: 6407: 6405: 6398: 6397: 6382: 6381: 6363: 6362: 6339: 6337: 6336: 6321: 6290: 6288: 6287: 6272: 6234: 6227: 6225: 6224: 6219: 6217: 6200: 6199: 6187: 6186: 6134: 6132: 6131: 6126: 6124: 6119: 6111: 6099: 6094: 6086: 6074: 6069: 6061: 6046: 6037: 6028: 6026: 6025: 6020: 6018: 6016: 6015: 5994: 5993: 5975: 5957: 5955: 5954: 5949: 5947: 5946: 5934: 5933: 5908: 5906: 5905: 5900: 5898: 5897: 5885: 5884: 5859: 5857: 5856: 5851: 5849: 5848: 5836: 5835: 5813: 5812: 5800: 5799: 5774: 5772: 5771: 5766: 5714: 5698: 5696: 5695: 5690: 5688: 5684: 5683: 5661: 5660: 5645: 5644: 5628: 5627: 5605: 5604: 5589: 5588: 5565: 5563: 5562: 5557: 5546: 5545: 5533: 5532: 5516: 5514: 5513: 5508: 5469: 5460: 5451: 5427: 5395: 5386: 5377: 5368: 5359: 5350: 5341: 5332: 5323: 5307: 5282: 5273: 5264: 5255: 5247:, which shrinks 5246: 5237: 5228: 5219: 5210: 5201: 5185: 5160: 5151: 5131: 5122: 5113: 5104: 5095: 5086: 5068:degenerate cases 5040: 5026:is the distance 5025: 5021: 5012: 5003: 4994: 4985: 4981: 4979: 4978: 4973: 4971: 4969: 4968: 4967: 4955: 4954: 4944: 4936: 4927: 4919: 4910: 4886: 4884: 4883: 4878: 4876: 4872: 4868: 4865: 4864: 4855: 4854: 4842: 4841: 4826: 4825: 4816: 4815: 4803: 4802: 4790: 4789: 4778: 4749: 4745: 4744: 4743: 4742: 4730: 4729: 4716: 4715: 4714: 4702: 4701: 4686: 4683: 4657: 4643: 4639: 4635: 4629: 4627: 4626: 4621: 4619: 4600: 4599: 4583: 4582: 4554: 4553: 4537: 4536: 4508: 4507: 4491: 4490: 4462: 4461: 4445: 4444: 4422: 4418: 4400: 4382: 4364: 4346: 4328: 4289:projective plane 4276:degenerate cases 4265: 4230: 4228: 4227: 4222: 4220: 4180: 4175: 4167: 4162: 4157: 4149: 4145: 4100: 4095: 4087: 4082: 4077: 4069: 4066: 4053: 4051: 4050: 4045: 4043: 4030: 4025: 4017: 4012: 4007: 3999: 3985: 3980: 3972: 3967: 3962: 3954: 3939: 3934: 3926: 3921: 3916: 3908: 3894: 3889: 3881: 3876: 3871: 3863: 3850: 3846: 3845: 3840: 3836: 3835: 3830: 3826: 3825: 3820: 3816: 3815: 3810: 3796: 3794: 3793: 3788: 3783: 3778: 3770: 3765: 3760: 3752: 3747: 3742: 3734: 3729: 3724: 3716: 3701: 3693: 3689: 3685: 3639: 3637: 3636: 3631: 3626: 3625: 3613: 3612: 3593: 3591: 3590: 3585: 3574: 3573: 3545: 3543: 3542: 3537: 3523: 3522: 3503: 3501: 3500: 3495: 3493: 3492: 3480: 3479: 3458:circle inversion 3451: 3449: 3448: 3443: 3438: 3437: 3422: 3421: 3406: 3405: 3394: 3390: 3389: 3374: 3373: 3358: 3357: 3341: 3326: 3324: 3323: 3318: 3313: 3312: 3297: 3296: 3281: 3280: 3264: 3255: 3239: 3223: 3221: 3220: 3215: 3210: 3209: 3208: 3202: 3201: 3192: 3191: 3190: 3176: 3169: 3167: 3166: 3153: 3148: 3139: 3137: 3134: 3129: 3117: 3112: 3111: 3110: 3104: 3103: 3094: 3093: 3083: 3076: 3073: 3068: 3059: 3058: 3049: 3044: 3043: 3042: 3036: 3035: 3031: 3018: 3017: 3013: 2999: 2985: 2976: 2974: 2973: 2968: 2963: 2962: 2961: 2955: 2954: 2945: 2944: 2943: 2929: 2922: 2920: 2919: 2907: 2902: 2901: 2896: 2895: 2887: 2881: 2877: 2876: 2875: 2869: 2868: 2859: 2858: 2848: 2841: 2839: 2838: 2826: 2821: 2820: 2815: 2814: 2806: 2795: 2793: 2792: 2787: 2785: 2782: 2777: 2764: 2759: 2750: 2745: 2744: 2729:by the distance 2728: 2719: 2716:lies not on the 2715: 2713: 2712: 2707: 2702: 2701: 2689: 2688: 2673: 2672: 2654: 2652: 2651: 2646: 2639: 2638: 2637: 2636: 2623: 2616: 2614: 2613: 2600: 2595: 2586: 2584: 2582: 2581: 2569: 2564: 2563: 2562: 2549: 2542: 2540: 2539: 2530: 2529: 2520: 2515: 2514: 2513: 2507: 2506: 2493: 2479: 2477: 2476: 2471: 2466: 2464: 2463: 2450: 2445: 2436: 2434: 2432: 2431: 2419: 2411: 2409: 2408: 2396: 2395: 2386: 2378: 2377: 2364: 2362: 2361: 2352: 2351: 2342: 2327: 2325: 2324: 2319: 2314: 2313: 2292: 2291: 2287: 2267: 2258: 2256: 2255: 2250: 2236: 2235: 2220: 2219: 2193: 2191: 2190: 2185: 2180: 2179: 2167: 2166: 2147: 2145: 2144: 2139: 2128: 2127: 2112: 2111: 2095: 2091: 2089: 2088: 2083: 2081: 2080: 2056: 2055: 2050: 2042: 2032: 2028: 2026: 2025: 2020: 2015: 2014: 1980: 1976: 1974: 1973: 1968: 1963: 1962: 1950: 1949: 1937: 1936: 1920: 1918: 1917: 1912: 1873: 1869: 1862: 1858: 1851: 1847: 1840: 1825: 1810: 1803: 1788: 1773: 1766: 1762: 1715: 1703: 1692: 1688: 1679: 1670: 1666: 1662: 1655: 1651: 1644: 1640: 1636: 1629: 1625: 1614: 1610: 1606: 1597: 1585: 1581: 1577: 1576: 1571: 1570: 1561: 1557: 1542: 1530: 1522: 1515: 1511: 1507: 1499: 1495: 1480: 1478: 1477: 1472: 1470: 1447: 1446: 1431: 1430: 1400: 1399: 1384: 1383: 1352: 1351: 1336: 1335: 1298: 1297: 1282: 1281: 1259: 1257: 1250: 1249: 1239: 1232: 1231: 1221: 1210: 1209: 1190: 1189: 1170: 1168: 1161: 1160: 1150: 1143: 1142: 1132: 1130: 1129: 1117: 1116: 1101: 1099: 1092: 1091: 1081: 1074: 1073: 1063: 1035: 1019: 1017: 1016: 1011: 1009: 1005: 1003: 996: 995: 985: 978: 977: 967: 955: 953: 945: 937: 921: 919: 911: 903: 858: 857: 841: 840: 816: 815: 797: 791: 776: 772: 770: 769: 764: 759: 758: 746: 745: 730: 729: 714: 713: 698: 697: 678: 660: 658: 657: 652: 647: 646: 634: 633: 609: 608: 574: 572: 571: 566: 549: 548: 533: 532: 502: 501: 486: 485: 458: 440: 428: 426: 425: 420: 418: 417: 405: 404: 380: 379: 339: 328: 320: 316: 312: 298: 291: 284: 280: 276: 272: 268: 261: 253: 249: 241: 230: 226: 222: 210: 206: 202: 198: 186: 185: 180: 176: 175: 171: 115: 108: 104: 76: 21: 8335: 8334: 8330: 8329: 8328: 8326: 8325: 8324: 8310: 8309: 8291: 8290: 8272: 8271: 8268: 8263: 8232: 8227: 8226: 8222: 8201: 8200: 8196: 8187: 8185: 8179: 8178: 8174: 8164: 8160: 8145: 8144: 8140: 8136: 8107: 8099: 8073: 8072: 8065: 8051: 8027: 8019: 8011: 8010: 8008: 7997: 7993: 7938: 7930: 7922: 7921: 7910: 7899: 7876: 7823: 7815:Main articles: 7804: 7800: 7796: 7792: 7785: 7783:Generalizations 7743: 7737: 7721: 7715: 7709: 7706: 7700: 7694: 7691: 7685: 7679: 7676: 7670: 7667: 7661: 7658: 7652: 7649: 7647:Monge's theorem 7643: 7625: 7619: 7614: 7576: 7554: 7541: 7536: 7535: 7502: 7489: 7473: 7472: 7443: 7430: 7414: 7413: 7389: 7376: 7352: 7339: 7329: 7328: 7304: 7291: 7280: 7279: 7251: 7238: 7227: 7226: 7209: 7177: 7164: 7159: 7158: 7142: 7141: 7119: 7106: 7093: 7074: 7061: 7055: 7054: 7032: 7019: 7006: 6987: 6974: 6968: 6967: 6957: 6944: 6931: 6912: 6899: 6893: 6892: 6882: 6869: 6856: 6837: 6824: 6812: 6811: 6806: 6800: 6797: 6791: 6788: 6782: 6779: 6773: 6770: 6764: 6761: 6755: 6744: 6738: 6729: 6722: 6719: 6713: 6710: 6704: 6701: 6695: 6692: 6686: 6679: 6673: 6670: 6664: 6657: 6652: 6646: 6643: 6637: 6630: 6610: 6609: 6604: 6592: 6578: 6577: 6565: 6552: 6542: 6536: 6535: 6528: 6516: 6512: 6489: 6473: 6472: 6465: 6461: 6454: 6450: 6447: 6441: 6438: 6432: 6420: 6403: 6402: 6389: 6373: 6354: 6347: 6341: 6340: 6328: 6298: 6292: 6291: 6279: 6249: 6237: 6236: 6229: 6215: 6214: 6201: 6191: 6178: 6175: 6174: 6161: 6137: 6136: 6112: 6087: 6062: 6049: 6048: 6045: 6039: 6036: 6030: 6007: 5985: 5963: 5962: 5938: 5925: 5911: 5910: 5889: 5876: 5862: 5861: 5840: 5827: 5804: 5791: 5777: 5776: 5717: 5716: 5700: 5686: 5685: 5675: 5668: 5652: 5636: 5630: 5629: 5619: 5612: 5596: 5580: 5568: 5567: 5537: 5524: 5519: 5518: 5472: 5471: 5468: 5462: 5459: 5453: 5449: 5442: 5435: 5429: 5425: 5418: 5411: 5405: 5402: 5394: 5388: 5385: 5379: 5376: 5370: 5367: 5361: 5358: 5352: 5349: 5343: 5340: 5334: 5331: 5325: 5322: 5315: 5309: 5306: 5300: 5281: 5275: 5272: 5266: 5263: 5257: 5254: 5248: 5245: 5239: 5236: 5230: 5227: 5221: 5218: 5212: 5209: 5203: 5200: 5193: 5187: 5184: 5178: 5159: 5153: 5150: 5143: 5137: 5130: 5124: 5121: 5115: 5112: 5106: 5103: 5097: 5094: 5088: 5085: 5079: 5076: 5063: 5047: 5039: 5033: 5027: 5023: 5020: 5014: 5011: 5005: 5002: 4996: 4993: 4987: 4983: 4959: 4946: 4945: 4937: 4930: 4929: 4925: 4918: 4912: 4909: 4903: 4874: 4873: 4856: 4846: 4833: 4817: 4807: 4794: 4779: 4773: 4757: 4751: 4750: 4734: 4721: 4706: 4693: 4691: 4687: 4672: 4660: 4659: 4645: 4641: 4637: 4633: 4617: 4616: 4591: 4584: 4574: 4571: 4570: 4545: 4538: 4528: 4525: 4524: 4499: 4492: 4482: 4479: 4478: 4453: 4446: 4436: 4427: 4426: 4420: 4416: 4409: 4402: 4398: 4391: 4384: 4380: 4373: 4366: 4362: 4355: 4348: 4344: 4337: 4330: 4326: 4319: 4312: 4301: 4263: 4253: 4218: 4217: 4168: 4150: 4146: 4138: 4137: 4088: 4070: 4058: 4057: 4041: 4040: 4018: 4000: 3995: 3973: 3955: 3950: 3949: 3927: 3909: 3904: 3882: 3864: 3853: 3852: 3848: 3843: 3842: 3838: 3833: 3832: 3828: 3823: 3822: 3818: 3813: 3812: 3808: 3771: 3753: 3735: 3717: 3710: 3709: 3699: 3691: 3687: 3683: 3677: 3665:regular polygon 3645: 3617: 3604: 3596: 3595: 3565: 3557: 3556: 3514: 3506: 3505: 3484: 3471: 3463: 3462: 3429: 3413: 3397: 3381: 3365: 3349: 3344: 3343: 3336: 3330: 3304: 3288: 3272: 3267: 3266: 3263: 3257: 3250: 3244: 3234: 3228: 3193: 3182: 3178: 3171: 3158: 3095: 3085: 3078: 3050: 3019: 3001: 2994: 2988: 2987: 2984: 2978: 2946: 2935: 2931: 2924: 2911: 2884: 2860: 2850: 2843: 2830: 2803: 2798: 2797: 2736: 2731: 2730: 2727: 2721: 2717: 2693: 2680: 2664: 2659: 2658: 2618: 2605: 2573: 2544: 2531: 2521: 2498: 2488: 2482: 2481: 2455: 2423: 2400: 2387: 2369: 2353: 2343: 2330: 2329: 2305: 2275: 2270: 2269: 2266: 2260: 2227: 2211: 2206: 2205: 2171: 2158: 2150: 2149: 2119: 2103: 2098: 2097: 2096:-axis at point 2093: 2072: 2043: 2035: 2034: 2030: 2006: 1983: 1982: 1978: 1977:The tangent at 1954: 1941: 1928: 1923: 1922: 1885: 1884: 1881: 1871: 1867: 1860: 1856: 1849: 1845: 1839: 1833: 1827: 1824: 1818: 1812: 1808: 1802: 1796: 1790: 1787: 1781: 1775: 1771: 1764: 1761: 1754: 1747: 1740: 1733: 1726: 1720: 1713: 1701: 1690: 1687: 1681: 1678: 1672: 1668: 1665: 1658: 1657: 1654: 1647: 1646: 1642: 1639: 1632: 1631: 1628: 1621: 1620: 1612: 1608: 1605: 1599: 1596: 1590: 1583: 1579: 1574: 1573: 1568: 1567: 1559: 1555: 1550:may be used to 1548:Thales' theorem 1540: 1528: 1520: 1513: 1509: 1505: 1497: 1493: 1486: 1468: 1467: 1457: 1438: 1422: 1391: 1375: 1363: 1362: 1343: 1327: 1308: 1289: 1273: 1261: 1260: 1241: 1240: 1223: 1222: 1201: 1191: 1181: 1172: 1171: 1152: 1151: 1134: 1133: 1121: 1108: 1083: 1082: 1065: 1064: 1052: 1040: 1039: 1023: 1007: 1006: 987: 986: 969: 968: 956: 946: 938: 933: 932: 922: 912: 904: 860: 859: 849: 842: 832: 807: 781: 780: 774: 750: 737: 721: 705: 689: 681: 680: 676: 669: 662: 638: 625: 600: 583: 582: 540: 524: 493: 477: 463: 462: 456: 449: 442: 430: 429:with center at 409: 396: 371: 354: 353: 346: 330: 322: 318: 314: 310: 303:(sum to 180°). 293: 286: 282: 278: 274: 270: 266: 259: 251: 247: 239: 228: 224: 220: 208: 204: 200: 196: 183: 182: 178: 173: 169: 168: 142:map projections 122:transformations 113: 106: 102: 101:A tangent line 99: 74: 46:at exactly one 28: 23: 22: 15: 12: 11: 5: 8333: 8331: 8323: 8322: 8312: 8311: 8308: 8307: 8288: 8267: 8266:External links 8264: 8262: 8261: 8220: 8194: 8172: 8158: 8152:Stack Exchange 8137: 8135: 8132: 8120: 8113: 8110: 8105: 8102: 8095: 8092: 8089: 8086: 8083: 8080: 8033: 8030: 8025: 8022: 7981: 7978: 7975: 7972: 7969: 7966: 7963: 7960: 7957: 7954: 7951: 7944: 7941: 7936: 7933: 7873:unit hyperbola 7817:Pole and polar 7799:. The points 7784: 7781: 7739:Main article: 7736: 7733: 7719: 7713: 7704: 7698: 7689: 7683: 7674: 7665: 7656: 7645:Main article: 7642: 7639: 7635:pulley problem 7621:Main article: 7618: 7615: 7613: 7610: 7588: 7583: 7579: 7575: 7572: 7569: 7566: 7561: 7557: 7553: 7548: 7544: 7529: 7528: 7515: 7509: 7505: 7501: 7496: 7492: 7487: 7483: 7480: 7469: 7456: 7450: 7446: 7442: 7437: 7433: 7428: 7424: 7421: 7410: 7396: 7392: 7388: 7383: 7379: 7375: 7372: 7369: 7365: 7359: 7355: 7351: 7346: 7342: 7337: 7325: 7311: 7307: 7303: 7298: 7294: 7290: 7287: 7276: 7258: 7254: 7250: 7245: 7241: 7237: 7234: 7218:multiplicities 7208: 7205: 7189: 7184: 7180: 7176: 7171: 7167: 7138: 7133: 7129: 7125: 7122: 7120: 7118: 7113: 7109: 7105: 7100: 7096: 7092: 7089: 7086: 7081: 7077: 7073: 7068: 7064: 7060: 7057: 7056: 7051: 7046: 7042: 7038: 7035: 7033: 7031: 7026: 7022: 7018: 7013: 7009: 7005: 7002: 6999: 6994: 6990: 6986: 6981: 6977: 6973: 6970: 6969: 6966: 6963: 6960: 6958: 6956: 6951: 6947: 6943: 6938: 6934: 6930: 6927: 6924: 6919: 6915: 6911: 6906: 6902: 6898: 6895: 6894: 6891: 6888: 6885: 6883: 6881: 6876: 6872: 6868: 6863: 6859: 6855: 6852: 6849: 6844: 6840: 6836: 6831: 6827: 6823: 6820: 6819: 6804: 6795: 6786: 6777: 6768: 6759: 6743: 6740: 6717: 6708: 6703:negative then 6699: 6690: 6683: 6682: 6677: 6668: 6655: 6650: 6641: 6614: 6608: 6605: 6599: 6595: 6591: 6588: 6583: 6580: 6579: 6572: 6568: 6564: 6561: 6556: 6553: 6551: 6548: 6547: 6545: 6496: 6492: 6488: 6485: 6480: 6445: 6436: 6401: 6396: 6392: 6388: 6385: 6380: 6376: 6372: 6369: 6366: 6361: 6357: 6353: 6350: 6348: 6346: 6343: 6342: 6335: 6331: 6327: 6324: 6319: 6316: 6313: 6310: 6307: 6304: 6301: 6299: 6297: 6294: 6293: 6286: 6282: 6278: 6275: 6270: 6267: 6264: 6261: 6258: 6255: 6252: 6250: 6248: 6245: 6244: 6213: 6210: 6207: 6204: 6202: 6198: 6194: 6190: 6185: 6181: 6177: 6176: 6173: 6170: 6167: 6164: 6162: 6160: 6157: 6154: 6151: 6148: 6145: 6144: 6122: 6118: 6115: 6109: 6106: 6102: 6097: 6093: 6090: 6084: 6081: 6077: 6072: 6068: 6065: 6059: 6056: 6043: 6034: 6014: 6010: 6006: 6003: 6000: 5997: 5992: 5988: 5984: 5981: 5978: 5973: 5970: 5945: 5941: 5937: 5932: 5928: 5924: 5921: 5918: 5896: 5892: 5888: 5883: 5879: 5875: 5872: 5869: 5847: 5843: 5839: 5834: 5830: 5826: 5823: 5820: 5816: 5811: 5807: 5803: 5798: 5794: 5790: 5787: 5784: 5764: 5761: 5758: 5754: 5751: 5748: 5745: 5742: 5739: 5736: 5733: 5730: 5727: 5724: 5682: 5678: 5674: 5671: 5669: 5667: 5664: 5659: 5655: 5651: 5648: 5643: 5639: 5635: 5632: 5631: 5626: 5622: 5618: 5615: 5613: 5611: 5608: 5603: 5599: 5595: 5592: 5587: 5583: 5579: 5576: 5575: 5555: 5552: 5549: 5544: 5540: 5536: 5531: 5527: 5506: 5503: 5500: 5497: 5494: 5491: 5488: 5485: 5482: 5479: 5466: 5457: 5447: 5440: 5433: 5423: 5416: 5409: 5401: 5398: 5392: 5383: 5374: 5365: 5356: 5347: 5338: 5329: 5320: 5313: 5304: 5289: 5288: 5279: 5270: 5261: 5252: 5243: 5234: 5225: 5216: 5207: 5198: 5191: 5182: 5167: 5166: 5157: 5148: 5141: 5128: 5119: 5110: 5101: 5092: 5083: 5075: 5072: 5062: 5059: 5046: 5043: 5037: 5031: 5018: 5009: 5000: 4991: 4966: 4962: 4958: 4953: 4949: 4943: 4940: 4916: 4907: 4871: 4863: 4859: 4853: 4849: 4845: 4840: 4836: 4832: 4829: 4824: 4820: 4814: 4810: 4806: 4801: 4797: 4793: 4788: 4785: 4782: 4776: 4772: 4769: 4766: 4763: 4760: 4758: 4756: 4753: 4752: 4748: 4741: 4737: 4733: 4728: 4724: 4719: 4713: 4709: 4705: 4700: 4696: 4690: 4681: 4678: 4675: 4673: 4671: 4668: 4667: 4615: 4612: 4609: 4606: 4603: 4598: 4594: 4590: 4587: 4585: 4581: 4577: 4573: 4572: 4569: 4566: 4563: 4560: 4557: 4552: 4548: 4544: 4541: 4539: 4535: 4531: 4527: 4526: 4523: 4520: 4517: 4514: 4511: 4506: 4502: 4498: 4495: 4493: 4489: 4485: 4481: 4480: 4477: 4474: 4471: 4468: 4465: 4460: 4456: 4452: 4449: 4447: 4443: 4439: 4435: 4434: 4414: 4407: 4396: 4389: 4378: 4371: 4360: 4353: 4342: 4335: 4324: 4317: 4300: 4297: 4252: 4249: 4216: 4213: 4210: 4207: 4204: 4201: 4198: 4195: 4192: 4189: 4186: 4183: 4178: 4174: 4171: 4165: 4160: 4156: 4153: 4147: 4143: 4140: 4139: 4136: 4133: 4130: 4127: 4124: 4121: 4118: 4115: 4112: 4109: 4106: 4103: 4098: 4094: 4091: 4085: 4080: 4076: 4073: 4067: 4065: 4039: 4036: 4033: 4028: 4024: 4021: 4015: 4010: 4006: 4003: 3996: 3994: 3991: 3988: 3983: 3979: 3976: 3970: 3965: 3961: 3958: 3952: 3951: 3948: 3945: 3942: 3937: 3933: 3930: 3924: 3919: 3915: 3912: 3905: 3903: 3900: 3897: 3892: 3888: 3885: 3879: 3874: 3870: 3867: 3861: 3860: 3786: 3781: 3777: 3774: 3768: 3763: 3759: 3756: 3750: 3745: 3741: 3738: 3732: 3727: 3723: 3720: 3676: 3673: 3644: 3641: 3629: 3624: 3620: 3616: 3611: 3607: 3603: 3583: 3580: 3577: 3572: 3568: 3564: 3551:pole and polar 3535: 3532: 3529: 3526: 3521: 3517: 3513: 3491: 3487: 3483: 3478: 3474: 3470: 3453: 3452: 3441: 3436: 3432: 3428: 3425: 3420: 3416: 3412: 3409: 3404: 3400: 3393: 3388: 3384: 3380: 3377: 3372: 3368: 3364: 3361: 3356: 3352: 3334: 3327: 3316: 3311: 3307: 3303: 3300: 3295: 3291: 3287: 3284: 3279: 3275: 3261: 3248: 3241: 3232: 3213: 3207: 3200: 3196: 3189: 3185: 3181: 3175: 3165: 3161: 3157: 3152: 3147: 3143: 3133: 3128: 3124: 3120: 3115: 3109: 3102: 3098: 3092: 3088: 3082: 3072: 3067: 3063: 3057: 3053: 3047: 3041: 3034: 3030: 3026: 3022: 3016: 3012: 3008: 3004: 2998: 2982: 2966: 2960: 2953: 2949: 2942: 2938: 2934: 2928: 2918: 2914: 2910: 2905: 2900: 2893: 2890: 2880: 2874: 2867: 2863: 2857: 2853: 2847: 2837: 2833: 2829: 2824: 2819: 2812: 2809: 2781: 2776: 2772: 2768: 2763: 2758: 2754: 2748: 2743: 2739: 2725: 2705: 2700: 2696: 2692: 2687: 2683: 2679: 2676: 2671: 2667: 2644: 2635: 2630: 2627: 2622: 2612: 2608: 2604: 2599: 2594: 2590: 2580: 2576: 2572: 2567: 2561: 2556: 2553: 2548: 2538: 2534: 2528: 2524: 2518: 2512: 2505: 2501: 2497: 2492: 2469: 2462: 2458: 2454: 2449: 2444: 2440: 2430: 2426: 2422: 2417: 2414: 2407: 2403: 2399: 2394: 2390: 2384: 2381: 2376: 2372: 2367: 2360: 2356: 2350: 2346: 2340: 2337: 2317: 2312: 2308: 2304: 2301: 2298: 2295: 2290: 2286: 2282: 2278: 2264: 2248: 2245: 2242: 2239: 2234: 2230: 2226: 2223: 2218: 2214: 2183: 2178: 2174: 2170: 2165: 2161: 2157: 2137: 2134: 2131: 2126: 2122: 2118: 2115: 2110: 2106: 2079: 2075: 2071: 2068: 2065: 2062: 2059: 2053: 2049: 2046: 2018: 2013: 2009: 2005: 2002: 1999: 1996: 1993: 1990: 1966: 1961: 1957: 1953: 1948: 1944: 1940: 1935: 1931: 1910: 1907: 1904: 1901: 1898: 1895: 1892: 1880: 1877: 1876: 1875: 1864: 1853: 1842: 1837: 1831: 1822: 1816: 1811:for the lines 1805: 1800: 1794: 1785: 1779: 1768: 1759: 1752: 1745: 1738: 1731: 1724: 1717: 1685: 1676: 1663: 1652: 1637: 1626: 1617: 1616: 1607:of the circle 1603: 1594: 1587: 1533: 1532: 1517: 1508:is drawn from 1485: 1482: 1466: 1463: 1460: 1458: 1456: 1453: 1450: 1445: 1441: 1437: 1434: 1429: 1425: 1421: 1418: 1415: 1412: 1409: 1406: 1403: 1398: 1394: 1390: 1387: 1382: 1378: 1374: 1371: 1368: 1365: 1364: 1361: 1358: 1355: 1350: 1346: 1342: 1339: 1334: 1330: 1326: 1323: 1320: 1317: 1314: 1311: 1309: 1307: 1304: 1301: 1296: 1292: 1288: 1285: 1280: 1276: 1272: 1269: 1266: 1263: 1262: 1256: 1253: 1248: 1244: 1238: 1235: 1230: 1226: 1219: 1216: 1213: 1208: 1204: 1200: 1197: 1194: 1192: 1188: 1184: 1180: 1177: 1174: 1173: 1167: 1164: 1159: 1155: 1149: 1146: 1141: 1137: 1128: 1124: 1120: 1115: 1111: 1107: 1104: 1098: 1095: 1090: 1086: 1080: 1077: 1072: 1068: 1061: 1058: 1055: 1053: 1051: 1048: 1047: 1002: 999: 994: 990: 984: 981: 976: 972: 965: 962: 959: 957: 952: 949: 944: 941: 935: 934: 931: 928: 925: 923: 918: 915: 910: 907: 901: 898: 895: 892: 889: 886: 883: 880: 877: 874: 871: 868: 865: 862: 861: 856: 852: 848: 845: 843: 839: 835: 831: 828: 825: 822: 819: 814: 810: 806: 803: 800: 794: 789: 788: 762: 757: 753: 749: 744: 740: 736: 733: 728: 724: 720: 717: 712: 708: 704: 701: 696: 692: 688: 674: 667: 650: 645: 641: 637: 632: 628: 624: 621: 618: 615: 612: 607: 603: 599: 596: 593: 590: 564: 561: 558: 555: 552: 547: 543: 539: 536: 531: 527: 523: 520: 517: 514: 511: 508: 505: 500: 496: 492: 489: 484: 480: 476: 473: 470: 454: 447: 416: 412: 408: 403: 399: 395: 392: 389: 386: 383: 378: 374: 370: 367: 364: 361: 345: 342: 219:in the circle 98: 95: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 8332: 8321: 8318: 8317: 8315: 8303: 8302: 8297: 8294: 8289: 8284: 8283: 8278: 8275: 8270: 8269: 8265: 8258: 8254: 8250: 8246: 8242: 8238: 8231: 8224: 8221: 8217: 8214:, p. 110, at 8213: 8212: 8205: 8198: 8195: 8183: 8180:Paul Kunkel. 8176: 8173: 8170: 8167: 8162: 8159: 8154: 8153: 8148: 8142: 8139: 8133: 8131: 8118: 8111: 8108: 8103: 8100: 8093: 8087: 8081: 8078: 8068: 8063: 8058: 8054: 8031: 8028: 8023: 8020: 8004: 8000: 7979: 7973: 7970: 7967: 7964: 7961: 7958: 7955: 7949: 7942: 7939: 7934: 7931: 7917: 7913: 7906: 7902: 7897: 7891: 7887: 7883: 7879: 7874: 7870: 7865: 7863: 7859: 7855: 7851: 7846: 7842: 7840: 7836: 7832: 7828: 7822: 7818: 7810: 7789: 7782: 7780: 7777: 7773: 7769: 7764: 7761: 7757: 7747: 7742: 7734: 7732: 7730: 7729:Gaspard Monge 7726: 7718: 7712: 7703: 7697: 7688: 7682: 7673: 7664: 7655: 7648: 7638: 7636: 7632: 7631: 7624: 7616: 7611: 7609: 7605: 7601: 7586: 7581: 7573: 7570: 7564: 7559: 7555: 7551: 7546: 7542: 7532: 7507: 7503: 7499: 7494: 7490: 7481: 7478: 7470: 7448: 7444: 7440: 7435: 7431: 7422: 7419: 7411: 7394: 7390: 7386: 7381: 7377: 7373: 7370: 7367: 7357: 7353: 7349: 7344: 7340: 7326: 7309: 7305: 7301: 7296: 7292: 7288: 7285: 7277: 7274: 7256: 7252: 7248: 7243: 7239: 7235: 7232: 7224: 7223: 7222: 7219: 7215: 7206: 7204: 7201: 7187: 7182: 7178: 7174: 7169: 7165: 7155: 7136: 7131: 7127: 7123: 7121: 7111: 7107: 7103: 7098: 7094: 7087: 7079: 7075: 7071: 7066: 7062: 7049: 7044: 7040: 7036: 7034: 7024: 7020: 7016: 7011: 7007: 7000: 6992: 6988: 6984: 6979: 6975: 6964: 6961: 6959: 6949: 6945: 6941: 6936: 6932: 6925: 6917: 6913: 6909: 6904: 6900: 6889: 6886: 6884: 6874: 6870: 6866: 6861: 6857: 6850: 6842: 6838: 6834: 6829: 6825: 6809: 6803: 6794: 6785: 6776: 6767: 6758: 6748: 6741: 6739: 6736: 6732: 6725: 6716: 6707: 6698: 6689: 6676: 6667: 6660: 6656: 6649: 6640: 6633: 6629: 6628: 6627: 6612: 6606: 6597: 6593: 6589: 6586: 6581: 6570: 6566: 6562: 6559: 6554: 6549: 6543: 6532: 6524: 6520: 6494: 6490: 6486: 6483: 6478: 6469: 6458: 6444: 6435: 6428: 6424: 6418: 6394: 6390: 6386: 6383: 6378: 6374: 6370: 6364: 6359: 6355: 6351: 6349: 6344: 6333: 6329: 6325: 6322: 6317: 6314: 6311: 6308: 6305: 6302: 6300: 6295: 6284: 6280: 6276: 6273: 6268: 6265: 6262: 6259: 6256: 6253: 6251: 6246: 6232: 6211: 6208: 6205: 6203: 6196: 6192: 6188: 6183: 6179: 6171: 6168: 6165: 6163: 6158: 6155: 6152: 6149: 6146: 6120: 6116: 6107: 6104: 6100: 6095: 6091: 6082: 6079: 6075: 6070: 6066: 6057: 6054: 6042: 6033: 6012: 6004: 5995: 5990: 5982: 5971: 5968: 5959: 5943: 5939: 5935: 5930: 5926: 5922: 5919: 5894: 5890: 5886: 5881: 5877: 5873: 5870: 5845: 5841: 5837: 5832: 5828: 5824: 5821: 5814: 5809: 5805: 5801: 5796: 5792: 5788: 5785: 5759: 5752: 5749: 5743: 5740: 5734: 5731: 5728: 5722: 5712: 5708: 5704: 5680: 5676: 5672: 5670: 5665: 5662: 5657: 5653: 5649: 5646: 5641: 5637: 5633: 5624: 5620: 5616: 5614: 5609: 5606: 5601: 5597: 5593: 5590: 5585: 5581: 5577: 5553: 5550: 5547: 5542: 5538: 5534: 5529: 5525: 5504: 5501: 5498: 5495: 5492: 5489: 5486: 5483: 5480: 5477: 5465: 5456: 5446: 5439: 5432: 5422: 5415: 5408: 5399: 5397: 5391: 5382: 5373: 5364: 5355: 5346: 5337: 5328: 5319: 5312: 5303: 5299:A new circle 5293: 5286: 5285: 5284: 5278: 5269: 5260: 5251: 5242: 5233: 5224: 5215: 5206: 5197: 5190: 5181: 5177:A new circle 5171: 5164: 5163: 5162: 5156: 5147: 5140: 5135: 5127: 5118: 5109: 5100: 5091: 5082: 5073: 5071: 5069: 5060: 5058: 5051: 5045:Inner tangent 5044: 5042: 5036: 5030: 5017: 5008: 4999: 4990: 4964: 4960: 4956: 4951: 4947: 4941: 4938: 4923: 4915: 4906: 4896: 4892: 4890: 4869: 4861: 4851: 4847: 4843: 4838: 4834: 4827: 4822: 4812: 4808: 4804: 4799: 4795: 4786: 4783: 4780: 4774: 4770: 4767: 4764: 4761: 4759: 4754: 4746: 4739: 4735: 4731: 4726: 4722: 4717: 4711: 4707: 4703: 4698: 4694: 4688: 4679: 4676: 4674: 4669: 4656: 4652: 4648: 4630: 4613: 4610: 4607: 4604: 4601: 4596: 4592: 4588: 4586: 4579: 4575: 4567: 4564: 4561: 4558: 4555: 4550: 4546: 4542: 4540: 4533: 4529: 4521: 4518: 4515: 4512: 4509: 4504: 4500: 4496: 4494: 4487: 4483: 4475: 4472: 4469: 4466: 4463: 4458: 4454: 4450: 4448: 4441: 4437: 4424: 4413: 4406: 4395: 4388: 4377: 4370: 4359: 4352: 4341: 4334: 4323: 4316: 4305: 4299:Outer tangent 4298: 4296: 4294: 4290: 4286: 4282: 4277: 4273: 4262: 4257: 4250: 4248: 4246: 4245:parallelogram 4242: 4237: 4234: 4231: 4211: 4208: 4205: 4199: 4193: 4190: 4187: 4181: 4172: 4169: 4163: 4154: 4151: 4141: 4131: 4128: 4125: 4119: 4113: 4110: 4107: 4101: 4092: 4089: 4083: 4074: 4071: 4055: 4037: 4034: 4031: 4022: 4019: 4013: 4004: 4001: 3992: 3989: 3986: 3977: 3974: 3968: 3959: 3956: 3946: 3943: 3940: 3931: 3928: 3922: 3913: 3910: 3901: 3898: 3895: 3886: 3883: 3877: 3868: 3865: 3801: 3797: 3784: 3775: 3772: 3766: 3757: 3754: 3748: 3739: 3736: 3730: 3721: 3718: 3707: 3705: 3704:Pitot theorem 3697: 3682: 3674: 3672: 3670: 3666: 3662: 3658: 3654: 3650: 3642: 3640: 3627: 3622: 3618: 3614: 3609: 3605: 3601: 3594:has equation 3578: 3575: 3570: 3566: 3554: 3552: 3546: 3533: 3527: 3524: 3519: 3515: 3489: 3485: 3481: 3476: 3472: 3468: 3460: 3459: 3439: 3434: 3430: 3426: 3423: 3418: 3414: 3410: 3407: 3402: 3398: 3391: 3386: 3382: 3378: 3375: 3370: 3366: 3362: 3359: 3354: 3350: 3340: 3333: 3328: 3314: 3309: 3305: 3301: 3298: 3293: 3289: 3285: 3282: 3277: 3273: 3260: 3254: 3247: 3242: 3238: 3231: 3226: 3225: 3224: 3211: 3198: 3194: 3187: 3183: 3179: 3163: 3159: 3155: 3150: 3145: 3141: 3131: 3126: 3122: 3118: 3113: 3100: 3096: 3090: 3086: 3070: 3065: 3061: 3055: 3051: 3045: 3032: 3028: 3024: 3020: 3014: 3010: 3006: 3002: 2981: 2964: 2951: 2947: 2940: 2936: 2932: 2916: 2912: 2908: 2903: 2898: 2888: 2878: 2865: 2861: 2855: 2851: 2835: 2831: 2827: 2822: 2817: 2807: 2779: 2774: 2770: 2766: 2761: 2756: 2752: 2746: 2741: 2737: 2724: 2698: 2694: 2690: 2685: 2681: 2674: 2669: 2665: 2655: 2642: 2628: 2625: 2610: 2606: 2602: 2597: 2592: 2588: 2578: 2574: 2570: 2565: 2554: 2551: 2536: 2532: 2526: 2522: 2516: 2503: 2499: 2495: 2467: 2460: 2456: 2452: 2447: 2442: 2438: 2428: 2424: 2420: 2415: 2412: 2405: 2401: 2397: 2392: 2388: 2382: 2379: 2374: 2370: 2365: 2358: 2354: 2348: 2344: 2338: 2335: 2310: 2306: 2302: 2299: 2293: 2288: 2284: 2280: 2276: 2263: 2246: 2240: 2237: 2232: 2228: 2221: 2216: 2212: 2198: 2194: 2181: 2176: 2172: 2168: 2163: 2159: 2155: 2132: 2129: 2124: 2120: 2113: 2108: 2104: 2077: 2069: 2066: 2063: 2057: 2047: 2044: 2016: 2011: 2007: 2003: 2000: 1997: 1994: 1991: 1988: 1981:has equation 1964: 1959: 1955: 1951: 1946: 1942: 1938: 1933: 1929: 1905: 1902: 1899: 1893: 1890: 1878: 1865: 1854: 1843: 1836: 1830: 1821: 1815: 1806: 1799: 1793: 1784: 1778: 1769: 1758: 1751: 1744: 1737: 1730: 1723: 1718: 1711: 1710: 1709: 1707: 1699: 1694: 1684: 1675: 1661: 1650: 1635: 1624: 1602: 1593: 1588: 1565: 1564: 1563: 1553: 1549: 1537: 1526: 1525:perpendicular 1518: 1503: 1502: 1501: 1491: 1483: 1481: 1464: 1461: 1459: 1451: 1448: 1443: 1439: 1427: 1423: 1419: 1416: 1410: 1404: 1401: 1396: 1392: 1380: 1376: 1372: 1369: 1356: 1353: 1348: 1344: 1332: 1328: 1324: 1321: 1315: 1312: 1310: 1302: 1299: 1294: 1290: 1278: 1274: 1270: 1267: 1254: 1251: 1246: 1242: 1236: 1233: 1228: 1224: 1214: 1211: 1206: 1202: 1195: 1193: 1186: 1182: 1178: 1175: 1165: 1162: 1157: 1153: 1147: 1144: 1139: 1135: 1126: 1122: 1118: 1113: 1109: 1105: 1102: 1096: 1093: 1088: 1084: 1078: 1075: 1070: 1066: 1059: 1056: 1054: 1049: 1037: 1034: 1030: 1026: 1020: 1000: 997: 992: 988: 982: 979: 974: 970: 963: 960: 958: 950: 947: 942: 939: 929: 926: 924: 916: 913: 908: 905: 896: 893: 890: 884: 881: 875: 872: 869: 863: 854: 850: 846: 844: 837: 829: 826: 823: 817: 812: 804: 801: 798: 778: 760: 755: 751: 747: 742: 734: 731: 726: 722: 715: 710: 702: 699: 694: 690: 673: 666: 648: 643: 639: 635: 630: 622: 619: 616: 610: 605: 597: 594: 591: 580: 575: 562: 559: 553: 550: 545: 541: 529: 525: 521: 518: 512: 506: 503: 498: 494: 482: 478: 474: 471: 460: 453: 446: 438: 434: 414: 410: 406: 401: 393: 390: 387: 381: 376: 368: 365: 362: 351: 343: 341: 338: 334: 326: 309: 304: 302: 301:supplementary 297: 290: 263: 257: 236: 232: 218: 214: 194: 166: 161: 157: 155: 149: 147: 143: 139: 135: 131: 127: 123: 119: 111: 96: 94: 92: 88: 84: 80: 79:perpendicular 73: 69: 65: 62:. Since the 61: 57: 56:constructions 53: 49: 45: 41: 37: 33: 19: 8299: 8280: 8243:(1): 34–46, 8240: 8236: 8223: 8216:Google Books 8209: 8203: 8197: 8186:. Retrieved 8175: 8161: 8150: 8141: 8066: 8056: 8052: 8002: 7998: 7915: 7911: 7904: 7900: 7889: 7885: 7881: 7877: 7866: 7847: 7843: 7833:) case of a 7824: 7767: 7765: 7759: 7753: 7727:altogether. 7716: 7710: 7701: 7695: 7686: 7680: 7671: 7662: 7653: 7650: 7634: 7630:belt problem 7628: 7626: 7623:Belt problem 7617:Belt problem 7612:Applications 7606: 7602: 7533: 7530: 7271:), which is 7210: 7202: 7156: 6810: 6801: 6792: 6783: 6774: 6765: 6756: 6753: 6737: 6730: 6723: 6714: 6705: 6696: 6687: 6684: 6674: 6665: 6658: 6647: 6638: 6631: 6530: 6522: 6518: 6467: 6456: 6442: 6433: 6426: 6422: 6419: 6230: 6040: 6031: 5960: 5710: 5706: 5702: 5699:Solving for 5463: 5454: 5452:with radius 5444: 5437: 5430: 5420: 5413: 5406: 5403: 5389: 5380: 5371: 5362: 5353: 5344: 5335: 5326: 5317: 5310: 5301: 5298: 5276: 5267: 5258: 5249: 5240: 5231: 5222: 5213: 5204: 5195: 5188: 5179: 5176: 5154: 5145: 5138: 5125: 5116: 5107: 5098: 5089: 5080: 5077: 5064: 5061:Construction 5056: 5034: 5028: 5015: 5006: 4997: 4988: 4913: 4904: 4901: 4654: 4650: 4646: 4631: 4425: 4411: 4404: 4393: 4386: 4375: 4368: 4357: 4350: 4339: 4332: 4321: 4314: 4310: 4285:affine plane 4269: 4238: 4235: 4232: 4056: 3841:(on segment 3831:(on segment 3821:(on segment 3811:(on segment 3806: 3708: 3678: 3646: 3549:Relation to 3548: 3547: 3456:Relation to 3455: 3454: 3338: 3331: 3258: 3252: 3245: 3236: 3229: 2979: 2722: 2656: 2261: 2203: 1882: 1834: 1828: 1819: 1813: 1797: 1791: 1782: 1776: 1756: 1749: 1742: 1735: 1728: 1721: 1706:straightedge 1695: 1682: 1673: 1659: 1648: 1633: 1622: 1618: 1600: 1591: 1546: 1487: 1038: 1032: 1028: 1024: 1021: 779: 671: 664: 576: 461: 451: 444: 436: 432: 347: 336: 332: 324: 305: 295: 288: 264: 245: 192: 190: 177:for any ray 150: 134:translations 118:secant lines 105:to a circle 100: 87:radial lines 64:tangent line 35: 29: 8211:online copy 4383:the points 3851:are equal: 3461:: Equation 3329:In case of 265:If a point 8188:2008-09-29 8134:References 7896:derivative 7884:) = (cosh 7839:bitangents 6790:and radii 6733:= −1 6661:= −1 5308:of radius 5186:of radius 4247:does not. 3702:. By the 1807:Similarly 1804:intersect, 238:The angle 138:inversions 124:, such as 110:intersects 91:orthogonal 8301:MathWorld 8282:MathWorld 8257:122408307 7971:⁡ 7959:⁡ 7920:, and is 7831:reducible 7776:inversion 7571:− 7500:− 7441:− 7350:− 7175:− 7104:− 7088:⋅ 7072:− 7017:− 7001:⋅ 6985:− 6942:− 6926:⋅ 6910:− 6867:− 6851:⋅ 6835:− 6590:− 6582:± 6563:− 6555:∓ 6487:− 6479:± 6365:− 6326:− 6277:− 6263:− 6114:Δ 6089:Δ 6064:Δ 6002:Δ 5980:Δ 5917:Δ 5887:− 5868:Δ 5838:− 5819:Δ 5802:− 5783:Δ 5747:Δ 5738:Δ 5726:Δ 5132:be their 4957:− 4844:− 4805:− 4784:− 4771:⁡ 4765:± 4755:β 4732:− 4704:− 4680:− 4670:γ 4614:α 4611:⁡ 4602:± 4568:α 4565:⁡ 4556:± 4522:α 4519:⁡ 4510:± 4476:α 4473:⁡ 4464:± 4287:; in the 4272:bitangent 4177:¯ 4159:¯ 4097:¯ 4079:¯ 4027:¯ 4009:¯ 3982:¯ 3964:¯ 3936:¯ 3918:¯ 3891:¯ 3873:¯ 3780:¯ 3762:¯ 3744:¯ 3726:¯ 3696:inscribed 3669:congruent 3180:− 3156:− 3114:± 2933:− 2892:→ 2811:→ 2657:If point 2603:− 2566:± 2504:± 2453:− 2416:± 2398:− 2383:± 2375:± 2311:± 2052:→ 1698:construct 1552:construct 1519:The line 1490:construct 1449:− 1420:− 1402:− 1373:− 1354:− 1325:− 1316:− 1300:− 1271:− 1252:− 1234:− 1212:− 1179:− 1163:− 1145:− 1094:− 1076:− 1060:− 998:− 980:− 964:− 894:− 873:− 827:− 802:− 732:− 700:− 620:− 595:− 551:− 522:− 504:− 475:− 391:− 366:− 93:circles. 8314:Category 7809:inverses 7216:and the 6471:is then 6449:, while 5194:− 5114:and let 4653:− 3661:triangle 3659:. Every 3657:incircle 2029:because 1578:, where 1527:line to 130:rotation 126:scalings 52:theorems 8320:Circles 8064:(where 8048:⁠ 8009:⁠ 7888:, sinh 6742:Vectors 5775:where 5136:, with 4986:can be 3653:polygon 1523:is the 1504:A line 1492:a line 285:, then 163:By the 81:to the 8255:  7996:since 7894:. The 7850:Möbius 7708:, and 7669:, and 6460:where 4982:Here, 4887:where 4768:arcsin 4658:with 4655:β 4651:γ 4647:α 4642:α 4421:α 4241:square 3837:) and 3395:  3256:point 2882:  2640:  679:where 140:, and 83:radius 68:circle 60:proofs 44:circle 8253:S2CID 8233:(PDF) 7772:scale 5144:> 5134:radii 4889:atan2 4684:atan2 4632:Here 3651:is a 3337:> 3235:< 2328:with 2148:with 335:= ½ ∠ 329:then 327:≤ 90° 308:chord 306:If a 72:point 70:at a 66:to a 48:point 38:is a 8069:= +1 8007:and 7968:cosh 7956:sinh 7819:and 7807:are 7803:and 7482:< 7374:< 7368:< 7236:> 6799:and 6781:and 6763:and 6728:and 6466:sin 6455:cos 6233:= ±1 5860:and 5461:and 5428:and 5229:and 5123:and 5105:and 5087:and 5078:Let 5013:and 4911:and 4636:and 4329:and 3849:ABCD 3700:ABCD 3684:ABCD 3243:For 3227:For 1883:Let 1870:and 1859:and 1848:and 1826:and 1789:and 1770:Let 1719:Let 1680:and 1656:and 1630:and 1598:and 321:and 299:are 292:and 281:and 89:and 58:and 40:line 34:, a 8245:doi 8067:j j 7898:of 7852:or 7848:In 7768:LLC 7760:LLL 6726:= 1 6672:to 6645:to 6634:= 1 6527:by 6453:is 6440:to 6038:to 5961:If 5436:= ( 5412:= ( 4995:or 4924:), 4608:cos 4562:sin 4516:cos 4470:sin 3827:), 3817:), 3694:is 352:is 337:TOM 333:PTM 325:PTM 296:TOS 289:TPS 193:two 179:PMN 77:is 30:In 8316:: 8298:. 8279:. 8251:, 8241:22 8239:, 8235:, 8149:. 8055:= 7864:. 7693:, 7660:, 7637:. 6735:. 6521:, 6425:, 5709:, 5705:, 5443:, 5419:, 5316:+ 5022:. 4649:= 4423:: 4410:, 4401:, 4392:, 4374:, 4365:, 4356:, 4338:, 4320:, 3844:DA 3834:CD 3824:BC 3814:AB 3679:A 3647:A 3251:= 1872:PG 1868:PF 1755:, 1748:, 1741:, 1734:, 1727:, 1708:: 1693:. 1660:PT 1649:PT 1634:OT 1623:OT 1575:OP 1569:OP 1562:: 1543:). 1036:. 1031:+ 1029:kx 1027:= 777:: 670:, 450:, 435:, 340:. 311:TM 231:. 184:PT 174:PN 172:· 170:PM 136:, 132:, 128:, 8304:. 8285:. 8247:: 8218:) 8208:( 8191:. 8119:. 8112:a 8109:d 8104:p 8101:d 8094:= 8091:) 8088:a 8085:( 8082:p 8079:j 8057:x 8053:y 8032:a 8029:d 8024:p 8021:d 8005:) 8003:a 8001:( 7999:p 7994:a 7980:. 7977:) 7974:a 7965:, 7962:a 7953:( 7950:= 7943:a 7940:d 7935:p 7932:d 7918:) 7916:a 7914:( 7912:p 7907:) 7905:a 7903:( 7901:p 7892:) 7890:a 7886:a 7882:a 7880:( 7878:p 7805:Q 7801:P 7797:q 7793:Q 7720:3 7717:C 7714:1 7711:C 7705:3 7702:C 7699:2 7696:C 7690:2 7687:C 7684:1 7681:C 7675:3 7672:C 7666:2 7663:C 7657:1 7654:C 7587:, 7582:2 7578:) 7574:r 7568:( 7565:= 7560:2 7556:y 7552:+ 7547:2 7543:x 7514:| 7508:2 7504:r 7495:1 7491:r 7486:| 7479:d 7455:| 7449:2 7445:r 7436:1 7432:r 7427:| 7423:= 7420:d 7395:2 7391:r 7387:+ 7382:1 7378:r 7371:d 7364:| 7358:2 7354:r 7345:1 7341:r 7336:| 7310:2 7306:r 7302:+ 7297:1 7293:r 7289:= 7286:d 7257:2 7253:r 7249:+ 7244:1 7240:r 7233:d 7188:, 7183:1 7179:t 7170:2 7166:t 7137:2 7132:2 7128:r 7124:= 7117:) 7112:2 7108:v 7099:2 7095:t 7091:( 7085:) 7080:2 7076:v 7067:2 7063:t 7059:( 7050:2 7045:1 7041:r 7037:= 7030:) 7025:1 7021:v 7012:1 7008:t 7004:( 6998:) 6993:1 6989:v 6980:1 6976:t 6972:( 6965:0 6962:= 6955:) 6950:1 6946:t 6937:2 6933:t 6929:( 6923:) 6918:1 6914:v 6905:1 6901:t 6897:( 6890:0 6887:= 6880:) 6875:1 6871:t 6862:2 6858:t 6854:( 6848:) 6843:2 6839:v 6830:2 6826:t 6822:( 6805:2 6802:r 6796:1 6793:r 6787:2 6784:v 6778:1 6775:v 6769:2 6766:t 6760:1 6757:t 6731:k 6724:k 6718:2 6715:c 6709:1 6706:c 6700:2 6697:r 6691:1 6688:r 6681:. 6678:1 6675:c 6669:2 6666:c 6659:k 6654:. 6651:2 6648:c 6642:1 6639:c 6632:k 6613:) 6607:R 6598:2 6594:R 6587:1 6571:2 6567:R 6560:1 6550:R 6544:( 6531:θ 6529:± 6525:) 6523:Y 6519:X 6517:( 6513:θ 6495:2 6491:R 6484:1 6468:θ 6462:θ 6457:θ 6451:R 6446:2 6443:c 6437:1 6434:c 6429:) 6427:Y 6423:X 6421:( 6400:) 6395:1 6391:y 6387:b 6384:+ 6379:1 6375:x 6371:a 6368:( 6360:1 6356:r 6352:= 6345:c 6334:2 6330:R 6323:1 6318:X 6315:k 6312:+ 6309:Y 6306:R 6303:= 6296:b 6285:2 6281:R 6274:1 6269:Y 6266:k 6260:X 6257:R 6254:= 6247:a 6231:k 6212:; 6209:1 6206:= 6197:2 6193:b 6189:+ 6184:2 6180:a 6172:, 6169:R 6166:= 6159:Y 6156:b 6153:+ 6150:X 6147:a 6121:d 6117:r 6108:= 6105:R 6101:, 6096:d 6092:y 6083:= 6080:Y 6076:, 6071:d 6067:x 6058:= 6055:X 6044:2 6041:c 6035:1 6032:c 6013:2 6009:) 6005:y 5999:( 5996:+ 5991:2 5987:) 5983:x 5977:( 5972:= 5969:d 5944:1 5940:r 5936:+ 5931:2 5927:r 5923:= 5920:r 5895:1 5891:r 5882:2 5878:r 5874:= 5871:r 5846:1 5842:y 5833:2 5829:y 5825:= 5822:y 5815:, 5810:1 5806:x 5797:2 5793:x 5789:= 5786:x 5763:) 5760:1 5757:( 5753:, 5750:r 5744:= 5741:y 5735:b 5732:+ 5729:x 5723:a 5713:) 5711:c 5707:b 5703:a 5701:( 5681:2 5677:r 5673:= 5666:c 5663:+ 5658:2 5654:y 5650:b 5647:+ 5642:2 5638:x 5634:a 5625:1 5621:r 5617:= 5610:c 5607:+ 5602:1 5598:y 5594:b 5591:+ 5586:1 5582:x 5578:a 5554:, 5551:1 5548:= 5543:2 5539:b 5535:+ 5530:2 5526:a 5505:, 5502:0 5499:= 5496:c 5493:+ 5490:y 5487:b 5484:+ 5481:x 5478:a 5467:2 5464:r 5458:1 5455:r 5450:) 5448:2 5445:y 5441:2 5438:x 5434:2 5431:c 5426:) 5424:1 5421:y 5417:1 5414:x 5410:1 5407:c 5393:1 5390:C 5384:3 5381:C 5375:1 5372:O 5366:2 5363:r 5357:1 5354:C 5348:2 5345:C 5339:2 5336:O 5330:1 5327:O 5321:2 5318:r 5314:1 5311:r 5305:3 5302:C 5280:1 5277:C 5271:3 5268:C 5262:1 5259:O 5253:2 5250:C 5244:2 5241:r 5235:2 5232:C 5226:1 5223:C 5217:2 5214:O 5208:1 5205:O 5199:2 5196:r 5192:1 5189:r 5183:3 5180:C 5158:1 5155:C 5149:2 5146:r 5142:1 5139:r 5129:2 5126:r 5120:1 5117:r 5111:2 5108:C 5102:1 5099:C 5093:2 5090:O 5084:1 5081:O 5038:2 5035:O 5032:1 5029:O 5024:d 5019:1 5016:O 5010:2 5007:O 5001:2 4998:r 4992:1 4989:r 4984:r 4965:2 4961:r 4952:1 4948:r 4942:r 4939:d 4926:S 4917:1 4914:O 4908:2 4905:O 4870:) 4862:2 4858:) 4852:1 4848:y 4839:2 4835:y 4831:( 4828:+ 4823:2 4819:) 4813:1 4809:x 4800:2 4796:x 4792:( 4787:r 4781:R 4775:( 4762:= 4747:) 4740:1 4736:x 4727:2 4723:x 4718:, 4712:1 4708:y 4699:2 4695:y 4689:( 4677:= 4638:r 4634:R 4605:R 4597:2 4593:y 4589:= 4580:4 4576:y 4559:R 4551:2 4547:x 4543:= 4534:4 4530:x 4513:r 4505:1 4501:y 4497:= 4488:3 4484:y 4467:r 4459:1 4455:x 4451:= 4442:3 4438:x 4417:) 4415:4 4412:y 4408:4 4405:x 4403:( 4399:) 4397:3 4394:y 4390:3 4387:x 4385:( 4381:) 4379:2 4376:y 4372:2 4369:x 4367:( 4363:) 4361:1 4358:y 4354:1 4351:x 4349:( 4345:) 4343:4 4340:y 4336:4 4333:x 4331:( 4327:) 4325:3 4322:y 4318:3 4315:x 4313:( 4264:S 4215:) 4212:a 4209:+ 4206:d 4203:( 4200:+ 4197:) 4194:c 4191:+ 4188:b 4185:( 4182:= 4173:A 4170:D 4164:+ 4155:C 4152:B 4142:= 4135:) 4132:d 4129:+ 4126:c 4123:( 4120:+ 4117:) 4114:b 4111:+ 4108:a 4105:( 4102:= 4093:D 4090:C 4084:+ 4075:B 4072:A 4038:. 4035:a 4032:= 4023:P 4020:A 4014:= 4005:S 4002:A 3993:, 3990:d 3987:= 3978:S 3975:D 3969:= 3960:R 3957:D 3947:, 3944:c 3941:= 3932:R 3929:C 3923:= 3914:Q 3911:C 3902:, 3899:b 3896:= 3887:Q 3884:B 3878:= 3869:P 3866:B 3839:S 3829:R 3819:Q 3809:P 3785:. 3776:A 3773:D 3767:+ 3758:C 3755:B 3749:= 3740:D 3737:C 3731:+ 3722:B 3719:A 3692:C 3688:C 3628:. 3623:2 3619:r 3615:= 3610:0 3606:x 3602:x 3582:) 3579:0 3576:, 3571:0 3567:x 3563:( 3553:: 3534:. 3531:) 3528:0 3525:, 3520:0 3516:x 3512:( 3490:2 3486:r 3482:= 3477:0 3473:x 3469:a 3440:. 3435:2 3431:r 3427:= 3424:y 3419:2 3415:y 3411:+ 3408:x 3403:2 3399:x 3392:, 3387:2 3383:r 3379:= 3376:y 3371:1 3367:y 3363:+ 3360:x 3355:1 3351:x 3339:r 3335:0 3332:d 3315:. 3310:2 3306:r 3302:= 3299:y 3294:0 3290:y 3286:+ 3283:x 3278:0 3274:x 3262:0 3259:P 3253:r 3249:0 3246:d 3237:r 3233:0 3230:d 3212:. 3206:) 3199:0 3195:x 3188:0 3184:y 3174:( 3164:2 3160:r 3151:2 3146:0 3142:d 3132:2 3127:0 3123:d 3119:r 3108:) 3101:0 3097:y 3091:0 3087:x 3081:( 3071:2 3066:0 3062:d 3056:2 3052:r 3046:= 3040:) 3033:2 3029:/ 3025:1 3021:y 3015:2 3011:/ 3007:1 3003:x 2997:( 2983:0 2980:P 2965:. 2959:) 2952:0 2948:x 2941:0 2937:y 2927:( 2917:0 2913:d 2909:1 2904:= 2899:2 2889:e 2879:, 2873:) 2866:0 2862:y 2856:0 2852:x 2846:( 2836:0 2832:d 2828:1 2823:= 2818:1 2808:e 2780:2 2775:0 2771:y 2767:+ 2762:2 2757:0 2753:x 2747:= 2742:0 2738:d 2726:0 2723:x 2718:x 2704:) 2699:0 2695:y 2691:, 2686:0 2682:x 2678:( 2675:= 2670:0 2666:P 2643:. 2634:) 2629:1 2626:0 2621:( 2611:2 2607:r 2598:2 2593:0 2589:x 2579:0 2575:x 2571:r 2560:) 2555:0 2552:1 2547:( 2537:0 2533:x 2527:2 2523:r 2517:= 2511:) 2500:b 2496:a 2491:( 2468:. 2461:2 2457:r 2448:2 2443:0 2439:x 2429:0 2425:x 2421:r 2413:= 2406:2 2402:a 2393:2 2389:r 2380:= 2371:b 2366:, 2359:0 2355:x 2349:2 2345:r 2339:= 2336:a 2316:) 2307:b 2303:, 2300:a 2297:( 2294:= 2289:2 2285:/ 2281:1 2277:P 2265:0 2262:P 2247:, 2244:) 2241:0 2238:, 2233:0 2229:x 2225:( 2222:= 2217:0 2213:P 2182:. 2177:2 2173:r 2169:= 2164:0 2160:x 2156:a 2136:) 2133:0 2130:, 2125:0 2121:x 2117:( 2114:= 2109:0 2105:P 2094:x 2078:T 2074:) 2070:b 2067:, 2064:a 2061:( 2058:= 2048:P 2045:O 2031:P 2017:, 2012:2 2008:r 2004:= 2001:y 1998:b 1995:+ 1992:x 1989:a 1979:P 1965:. 1960:2 1956:r 1952:= 1947:2 1943:y 1939:+ 1934:2 1930:x 1909:) 1906:b 1903:, 1900:a 1897:( 1894:= 1891:P 1874:. 1863:. 1861:G 1857:F 1852:. 1850:E 1846:D 1841:. 1838:1 1835:C 1832:2 1829:B 1823:2 1820:C 1817:1 1814:B 1809:E 1801:1 1798:B 1795:2 1792:A 1786:2 1783:B 1780:1 1777:A 1772:D 1767:. 1765:P 1760:2 1757:C 1753:1 1750:C 1746:2 1743:B 1739:1 1736:B 1732:2 1729:A 1725:1 1722:A 1714:P 1702:P 1691:C 1686:2 1683:T 1677:1 1674:T 1669:P 1664:2 1653:1 1643:C 1638:2 1627:1 1613:P 1609:C 1604:2 1601:T 1595:1 1592:T 1586:. 1584:C 1580:O 1560:C 1556:P 1541:P 1531:. 1529:a 1521:t 1516:; 1514:T 1510:O 1506:a 1498:T 1494:t 1465:0 1462:= 1455:) 1452:b 1444:1 1440:y 1436:( 1433:) 1428:1 1424:y 1417:y 1414:( 1411:+ 1408:) 1405:a 1397:1 1393:x 1389:( 1386:) 1381:1 1377:x 1370:x 1367:( 1360:) 1357:a 1349:1 1345:x 1341:( 1338:) 1333:1 1329:x 1322:x 1319:( 1313:= 1306:) 1303:b 1295:1 1291:y 1287:( 1284:) 1279:1 1275:y 1268:y 1265:( 1255:b 1247:1 1243:y 1237:a 1229:1 1225:x 1218:) 1215:x 1207:1 1203:x 1199:( 1196:= 1187:1 1183:y 1176:y 1166:b 1158:1 1154:y 1148:a 1140:1 1136:x 1127:1 1123:x 1119:+ 1114:1 1110:y 1106:+ 1103:x 1097:b 1089:1 1085:y 1079:a 1071:1 1067:x 1057:= 1050:y 1033:m 1025:y 1001:b 993:1 989:y 983:a 975:1 971:x 961:= 951:x 948:d 943:y 940:d 930:0 927:= 917:x 914:d 909:y 906:d 900:) 897:b 891:y 888:( 885:2 882:+ 879:) 876:a 870:x 867:( 864:2 855:2 851:r 847:= 838:2 834:) 830:b 824:y 821:( 818:+ 813:2 809:) 805:a 799:x 793:( 775:x 761:. 756:2 752:r 748:= 743:2 739:) 735:b 727:1 723:y 719:( 716:+ 711:2 707:) 703:a 695:1 691:x 687:( 677:) 675:1 672:y 668:1 665:x 663:( 649:, 644:2 640:r 636:= 631:2 627:) 623:b 617:y 614:( 611:+ 606:2 602:) 598:a 592:x 589:( 563:0 560:= 557:) 554:b 546:1 542:y 538:( 535:) 530:1 526:y 519:y 516:( 513:+ 510:) 507:a 499:1 495:x 491:( 488:) 483:1 479:x 472:x 469:( 457:) 455:1 452:y 448:1 445:x 443:( 439:) 437:b 433:a 431:( 415:2 411:r 407:= 402:2 398:) 394:b 388:y 385:( 382:+ 377:2 373:) 369:a 363:x 360:( 331:∠ 323:∠ 319:P 315:T 294:∠ 287:∠ 283:S 279:T 275:P 271:O 267:P 260:P 252:T 248:t 240:θ 229:P 225:P 221:C 209:P 205:O 201:P 197:P 114:T 107:C 103:t 75:P 20:)

Index

Tangent between two circles
Euclidean plane geometry
line
circle
point
theorems
constructions
proofs
tangent line
circle
point
perpendicular
radius
radial lines
orthogonal
intersects
secant lines
transformations
scalings
rotation
translations
inversions
map projections
incidence structure
reflection symmetry

power-of-a-point theorem
secant-tangent theorem
power of the point P

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