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Angle trisection

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1307: 1855: 4546: 2486: 1867: 2012: 1287: 2446:" is a geometric shape consisting of a semicircle and two orthogonal line segments, such that the length of the shorter segment is equal to the circle radius. Trisection is executed by leaning the end of the tomahawk's shorter segment on one ray, the circle's edge on the other, so that the "handle" (longer segment) crosses the angle's vertex; the trisection line runs between the vertex and the center of the semicircle. 4533: 31: 2435: 229: 244: 2419:
Hutcheson constructed a cylinder from the angle to be trisected by drawing an arc across the angle, completing it as a circle, and constructing from that circle a cylinder on which a, say, equilateral triangle was inscribed (a 360-degree angle divided in three). This was then "mapped" onto the angle
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The tomahawk produces the same geometric effect as the paper-folding method: the distance between circle center and the tip of the shorter segment is twice the distance of the radius, which is guaranteed to contact the angle. It is also equivalent to the use of an architects L-Ruler
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As is known ... every cubic construction can be traced back to the trisection of the angle and to the multiplication of the cube, that is, the extraction of the third root. I need only to show how these two classical tasks can be solved by means of the right angle
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While a tomahawk is constructible with compass and straightedge, it is not generally possible to construct a tomahawk in any desired position. Thus, the above construction does not contradict the nontrisectibility of angles with ruler and compass alone.
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that used a string instead of a compass and straight edge. A string can be used as either a straight edge (by stretching it) or a compass (by fixing one point and identifying another), but can also wrap around a cylinder, the key to Hutcheson's solution.
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Many incorrect methods of trisecting the general angle have been proposed. Some of these methods provide reasonable approximations; others (some of which are mentioned below) involve tools not permitted in the classical problem. The mathematician
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An angle can be trisected with a device that is essentially a four-pronged version of a compass, with linkages between the prongs designed to keep the three angles between adjacent prongs equal.
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Another means to trisect an arbitrary angle by a "small" step outside the Greek framework is via a ruler with two marks a set distance apart. The next construction is originally due to
2871: 395:. The argument below shows that it is impossible to construct a 20° angle. This implies that a 60° angle cannot be trisected, and thus that an arbitrary angle cannot be trisected. 2532: 3302: 1278:(types of folding operations) can construct cubic extensions (cube roots) of given lengths, whereas ruler-and-compass can construct only quadratic extensions (square roots). 2380: 335:
It follows that, given a segment that is defined to have unit length, the problem of angle trisection is equivalent to constructing a segment whose length is the root of a
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The general problem of angle trisection is solvable by using additional tools, and thus going outside of the original Greek framework of compass and straightedge.
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published a proof of the impossibility of classically trisecting an arbitrary angle in 1837. Wantzel's proof, restated in modern terminology, uses the concept of
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are equal, these three parallel lines delimit two equal segments on every other secant line, and in particular on their common perpendicular
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attempts at solution by naive enthusiasts. These "solutions" often involve mistaken interpretations of the rules, or are simply incorrect.
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Trisection, like many constructions impossible by ruler and compass, can easily be accomplished by the operations of paper folding, or
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straightedge. The diagrams we use show this construction for an acute angle, but it indeed works for any angle up to 180 degrees.
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can be used as a basis for the bisections. An approximation to any degree of accuracy can be obtained in a finite number of steps.
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with real coefficients can be solved geometrically with compass, straightedge, and an angle trisector if and only if it has three
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Trisection can be approximated by repetition of the compass and straightedge method for bisecting an angle. The geometric series
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Because it is defined in simple terms, but complex to prove unsolvable, the problem of angle trisection is a frequent subject of
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which can be used to make an instrument to trisect angles including Kempe's Trisector and Sylvester's Link Fan or Isoklinostat.
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of a transversal to two parallel lines. This proves the second desired equality, and thus the correctness of the construction.
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For the historical basis of Wantzel's proof in the earlier work of Ruffini and Abel, and its timing vis-a-vis Galois, see
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to solve for arbitrary angles. However, some special angles can be trisected: for example, it is trivial to trisect a
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which, if drawn on the plane using other methods, can be used to trisect arbitrary angles. Examples include the
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generated by these numbers. Therefore, any number that is constructible by a sequence of steps is a root of a
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It is possible to trisect an arbitrary angle by using tools other than straightedge and compass. For example,
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equal to one-third of a given arbitrary angle (or divide it into three equal angles), using only two tools:
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can be trivially trisected by ignoring the given angle and directly constructing an angle of measure
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using tools beyond an unmarked straightedge and a compass. The example shows trisection of any angle
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A tomahawk trisecting an angle. The tomahawk is formed by the thick lines and the shaded semicircle.
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number of equal parts. Archimedes described how to trisect an angle using the Archimedean spiral in
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is drawn. Then, the markedness of the ruler comes into play: one mark of the ruler is placed at
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Bieberbach's trisection of an angle (in blue) by means of a right triangular ruler (in red)
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multiplied by the product of one or more distinct Fermat primes, none of which divides
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Hutcheson, Thomas W. (May 2001). "Dividing Any Angle into Any Number of Equal Parts".
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A long article with many approximations & means going outside the Greek framework
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gives an expression relating the cosines of the original angle and its trisection:
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is equivalent to constructing two segments such that the ratio of their length is
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sides can be constructed with ruler, compass, and angle trisector if and only if
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equal to one third of a given arbitrary angle, using only two tools: an unmarked
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by a ruler with length equal to the radius of the circle, giving trisected angle
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is a relatively straightforward generalization of the proof given above that a
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Approximate angle trisection as an animation, max. error of the angle ≈ ±4E-8°
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Ludwig Bieberbach (1932) "Zur Lehre von den kubischen Konstruktionen",
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Three problems proved elusive, specifically, trisecting the angle,
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and of the same radius intersects the line supporting the edge in
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What is mathematics?: an elementary approach to ideas and methods
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See also Feedback on this article in vol. 93, March 2009, p. 156.
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as its second intersection with the edge. A circle centered at
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in such a way that the second leg of the ruler is tangent at
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the first desired equality. On the other hand, the triangle
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However, some angles can be trisected. For example, for any
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Geometric problems of antiquity, including angle trisection
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to be trisected, with a simple proof of similar triangles.
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Hyperbolic trisection and the spectrum of regular polygons
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equal parts with straightedge and compass if and only if
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Construction of an angle equal to one third a given angle
3097:"Angle trisection, the heptagon, and the triskaidecagon" 350:
in a single step from some given numbers is a root of a
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The problem of constructing an angle of a given measure
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Isaac, Rufus, "Two mathematical papers without words",
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be the horizontal line in the adjacent diagram. Angle
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has detailed some of these failed attempts in his book
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Any full set of angles on a straight line add to 180°,
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is placed on the drawing in the following manner: one
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This requires three facts from geometry (at right):
4477: 4355: 4305: 4279: 4201: 4183: 4082: 4075: 3931: 3893: 3710: 3318: 2636:{\displaystyle n=2^{r}3^{s}p_{1}p_{2}\cdots p_{k},} 1426:, by using that it is the intersection of the line 2691: 2635: 2526: 2458: 2374: 2315: 2283: 2241: 1980: 1832:{\displaystyle {\widehat {AEP}}={\widehat {EPD}},} 1831: 1769:{\displaystyle {\widehat {APE}}={\widehat {AEP}}.} 1768: 1694:{\displaystyle {\widehat {EPD}}={\widehat {DPS}},} 1693: 1556:{\displaystyle {\widehat {BPE}}={\widehat {EPD}}.} 1555: 1492: 2853:MacHale, Desmond. "Constructing integer angles", 2538:, using angle trisection by means of the tomahawk 1493:{\displaystyle {\widehat {EPD}}={\widehat {DPS}}} 1266:Mathematics of origami § Trisecting an angle 178:into an arbitrary set of equal segments, to draw 3146:Courant, Richard, Herbert Robbins, Ian Stewart, 2923:. Chapman and Hall Mathematics. pp. g. 58. 1981:{\displaystyle 2x(x^{2}+y^{2})=a(3x^{2}-y^{2}),} 2999:Journal für die reine und angewandte Mathematik 2656:are distinct primes greater than 3 of the form 2131:is drawn to make it obvious that line segments 2074:) is the subject of trisection. First, a point 1321:Journal für die reine und angewandte Mathematik 194:of equal or twice the area of a given polygon. 342:Every rational number is constructible. Every 3296: 2409:Thomas Hutcheson published an article in the 2393:Again, this construction stepped outside the 8: 2872:"Trisecting angles with ruler and compasses" 2794:Journal de Mathématiques Pures et Appliquées 2749: 2747: 2489:An animation of a neusis construction of a 2015:Trisection of the angle using a marked ruler 2043:The sum of angles of any triangle is 180°, 677:, but none of these is a root. Therefore, 235:. The displayed ones are marked — an ideal 4309: 4079: 3303: 3289: 3281: 3087: 3085: 3083: 1349:of the angle to be trisected, centered at 1326:Zur Lehre von den kubischen Konstruktionen 807:, which is a full circle plus the desired 2677: 2667: 2661: 2624: 2611: 2601: 2591: 2581: 2569: 2503: 2501: 2331: 2299: 2261: 2222: 1966: 1953: 1928: 1915: 1900: 1872:Trisection using the Maclaurin trisectrix 1807: 1806: 1784: 1783: 1781: 1744: 1743: 1721: 1720: 1718: 1713:of a circle are equal; this implies that 1669: 1668: 1646: 1645: 1643: 1531: 1530: 1508: 1507: 1505: 1471: 1470: 1448: 1447: 1445: 911:with the product of one or more distinct 765:is such an angle: five angles of measure 609:has degree 3, if it is reducible over by 205:. The problem of angle trisection reads: 2865: 2863: 2484: 2010: 1328:. He states therein (free translation): 1285: 2743: 2143:all have equal length. Now, triangles 1860:Trisection using the Archimedean spiral 1850: 1341:The construction begins with drawing a 118:proved that the problem, as stated, is 4586:Compass and straightedge constructions 4332:Latin translations of the 12th century 2109:. The mark on the circle is labeled 2029:, i.e., that uses tools other than an 1440:One has to prove the angle equalities 1430:and its perpendicular passing through 1084:Approximation by successive bisections 258:, a topic now typically combined with 4062:Straightedge and compass construction 3184:One link of marked ruler construction 2056:meet the third side at the same angle 1420:straightedge and compass construction 1353:on an edge of this angle, and having 354:of degree 2 with coefficients in the 93:straightedge and compass construction 7: 4027:Incircle and excircles of a triangle 3150:, Oxford University Press US, 1996. 2830:History of Mathematics: A Supplement 2459:§ With a right triangular ruler 2113:and the mark on the line is labeled 786:combine to make an angle of measure 466:. Then by the triple-angle formula, 2763:Mathematical Association of America 2527:{\displaystyle {\overline {OA}}=6} 1382:of its right angle passes through 25: 3104:The American Mathematical Monthly 1611:is the intersection of the lines 698:, and the minimal polynomial for 418:would be a power of two. Now let 99:. It concerns construction of an 4544: 4531: 2987:from the original on 2022-10-09. 2401:by using a marked straightedge. 1877:There are certain curves called 1865: 1853: 144:Background and problem statement 3073:48, 1975, p. 198. Reprinted in 2807:from the original on 2022-10-09 2453:As a tomahawk can be used as a 4364:A History of Greek Mathematics 3877:The Quadrature of the Parabola 3189:Another, mentioning Archimedes 2870:McLean, K. Robin (July 2008). 1972: 1943: 1934: 1908: 34:Angles may be trisected via a 1: 2473:With interconnected compasses 2375:{\displaystyle a=c+b=2b+b=3b} 2294:From the last two equations, 1883:trisectrix of Colin Maclaurin 1638:are congruent, and thus that 1302:With a right triangular ruler 1294:There are a number of simple 1045:. In the case of trisection ( 907:or the product of a power of 717:Angles which can be trisected 583:, the minimal polynomial for 216:an unmarked straightedge, and 4145:Intersecting secants theorem 3005:. Retrieved on June 2, 2017. 2692:{\displaystyle 2^{t}3^{u}+1} 2513: 1025:radians can be divided into 4140:Intersecting chords theorem 4007:Doctrine of proportionality 1839:since these two angles are 1345:passing through the vertex 4602: 3836:On the Sphere and Cylinder 3789:On the Sizes and Distances 2728:Morley's trisector theorem 2427: 2050:Any two equal sides of an 1398:to the circle centered at 1263: 996:angle is not trisectible. 919:Algebraic characterization 91:is a classical problem of 4538:Ancient Greece portal 4527: 4342:Philosophy of mathematics 4312: 4257:Ptolemy's table of chords 3312:Ancient Greek mathematics 3205:Other means of trisection 2888:10.1017/S0025557200183317 2833:, Springer, p. 130, 2827:Smorynski, Craig (2007), 923:Again, denote the set of 4571:Euclidean plane geometry 4209:Aristarchus's inequality 3782:On Conoids and Spheroids 3017:"Trisection of an Angle" 2971:Yates, Robert C (1942). 2946:"Trisection of an Angle" 2481:Uses of angle trisection 2284:{\displaystyle e+2b=180} 2165:is a straight line, and 1004:For any nonzero integer 174:found means to divide a 4317:Ancient Greek astronomy 4130:Inscribed angle theorem 4120:Greek geometric algebra 3775:Measurement of a Circle 3077:78, April 2005, p. 111. 2857:66, June 1982, 144–145. 2785:Wantzel, P M L (1837). 2242:{\displaystyle e+c=180} 2177:all have equal length, 2078:is drawn at an angle's 1847:With an auxiliary curve 709:So an angle of measure 166:Using only an unmarked 4551:Mathematics portal 4337:Non-Euclidean geometry 4292:Mouseion of Alexandria 4165:Tangent-secant theorem 4115:Geometric mean theorem 4100:Exterior angle theorem 4095:Angle bisector theorem 3799:On Sizes and Distances 3093:Gleason, Andrew Mattei 2974:The Trisection Problem 2693: 2637: 2539: 2528: 2439: 2376: 2317: 2285: 2243: 2082:, one unit apart from 2016: 1982: 1833: 1770: 1695: 1619:. It follows that the 1557: 1494: 1375:right triangular ruler 1311: 1291: 1008:, an angle of measure 1000:Other numbers of parts 971:is reducible over the 939:: An angle of measure 837:, an angle of measure 731:, an angle of measure 248: 240: 224:Proof of impossibility 163: 85: 4239:Pappus's area theorem 4175:Theorem of the gnomon 4052:Quadratrix of Hippias 3975:Circles of Apollonius 3923:Problem of Apollonius 3901:Constructible numbers 3725:Archimedes Palimpsest 2723:Constructible polygon 2694: 2638: 2529: 2488: 2437: 2399:allowed constructions 2377: 2318: 2286: 2244: 2117:. This ensures that 2014: 1983: 1887:Cartesian coordinates 1834: 1771: 1696: 1575:are parallel. As the 1558: 1495: 1309: 1289: 1033:is either a power of 713:cannot be trisected. 621:rational root theorem 543:to be the polynomial 246: 231: 162:has long been solved. 151: 33: 4455:prehistoric counting 4252:Ptolemy's inequality 4193:Apollonius's theorem 4032:Method of exhaustion 4002:Diophantine equation 3992:Circumscribed circle 3809:On the Moving Sphere 3267:sciencenews.org site 3133:on November 5, 2014. 3075:Mathematics Magazine 3070:Mathematics Magazine 3055:10.5951/MT.94.5.0400 2952:on February 25, 2012 2876:Mathematical Gazette 2855:Mathematical Gazette 2718:Constructible number 2660: 2568: 2500: 2330: 2316:{\displaystyle c=2b} 2298: 2260: 2252:Looking at triangle 2221: 2217:From Fact 1) above, 1899: 1780: 1717: 1642: 1504: 1444: 1414:and passing through 1290:Sylvester's Link Fan 1056:not be divisible by 623:, this root must be 284:triple-angle formula 186:, to construct many 172:Greek mathematicians 4581:History of geometry 4541: • 4347:Neusis construction 4267:Spiral of Theodorus 4160:Pythagorean theorem 4105:Euclidean algorithm 4047:Lune of Hippocrates 3916:Squaring the circle 3672:Theon of Alexandria 3347:Aristaeus the Elder 3043:Mathematics Teacher 3023:on November 4, 2013 2430:Tomahawk (geometry) 2412:Mathematics Teacher 2026:Neusis construction 2007:With a marked ruler 203:squaring the circle 190:, and to construct 131:neusis construction 36:neusis construction 4576:Unsolvable puzzles 4234:Menelaus's theorem 4224:Irrational numbers 4037:Parallel postulate 4012:Euclidean geometry 3980:Apollonian circles 3522:Isidore of Miletus 3246:Archimedean Spiral 3003:online-copie (GDZ) 2689: 2647:≥ 0 and where the 2633: 2540: 2524: 2467:Carpenter's Square 2440: 2372: 2313: 2281: 2239: 2052:isosceles triangle 2017: 1993:Archimedean spiral 1978: 1829: 1766: 1691: 1553: 1490: 1312: 1292: 702:is of degree  398:Denote the set of 391:, written 60°) is 362:whose degree is a 360:minimal polynomial 249: 241: 164: 138:pseudomathematical 86: 4558: 4557: 4523: 4522: 4275: 4274: 4262:Ptolemy's theorem 4135:Intercept theorem 3985:Apollonian gasket 3911:Doubling the cube 3884:The Sand Reckoner 3156:978-0-19-510519-3 2944:Jim Loy (2003) . 2930:978-0-412-34550-0 2772:978-0-88385-514-0 2755:Dudley, Underwood 2703:greater than 3). 2536:Andrew M. Gleason 2516: 2424:With a "tomahawk" 2097:and the other at 1891:implicit equation 1823: 1800: 1760: 1737: 1685: 1662: 1547: 1524: 1487: 1464: 1410:perpendicular to 1316:Ludwig Bieberbach 1037:or is a power of 945:may be trisected 344:irrational number 199:doubling the cube 97:Greek mathematics 16:(Redirected from 4593: 4549: 4548: 4536: 4535: 4534: 4310: 4297:Platonic Academy 4244:Problem II.8 of 4214:Crossbar theorem 4170:Thales's theorem 4110:Euclid's theorem 4080: 3997:Commensurability 3958:Axiomatic system 3906:Angle trisection 3871: 3861: 3823: 3813: 3803: 3793: 3769: 3759: 3742: 3305: 3298: 3291: 3282: 3222:2009-10-25) the 3135: 3134: 3132: 3126:. Archived from 3101: 3089: 3078: 3065: 3059: 3058: 3038: 3032: 3031: 3029: 3028: 3019:. Archived from 3012: 3006: 2995: 2989: 2988: 2986: 2979: 2968: 2962: 2961: 2959: 2957: 2948:. Archived from 2941: 2935: 2934: 2909: 2903: 2902: 2867: 2858: 2851: 2845: 2843: 2823: 2817: 2816: 2814: 2812: 2806: 2791: 2782: 2776: 2775: 2751: 2698: 2696: 2695: 2690: 2682: 2681: 2672: 2671: 2642: 2640: 2639: 2634: 2629: 2628: 2616: 2615: 2606: 2605: 2596: 2595: 2586: 2585: 2533: 2531: 2530: 2525: 2517: 2512: 2504: 2381: 2379: 2378: 2373: 2322: 2320: 2319: 2314: 2290: 2288: 2287: 2282: 2248: 2246: 2245: 2240: 2206: 2205: 2203: 2202: 2199: 2196: 2176: 2172: 2168: 2164: 2150: 2146: 2142: 2138: 2134: 2130: 2126: 2116: 2112: 2108: 2104: 2100: 2096: 2092: 2085: 2077: 2073: 2069: 2065: 1987: 1985: 1984: 1979: 1971: 1970: 1958: 1957: 1933: 1932: 1920: 1919: 1869: 1857: 1841:alternate angles 1838: 1836: 1835: 1830: 1825: 1824: 1819: 1808: 1802: 1801: 1796: 1785: 1775: 1773: 1772: 1767: 1762: 1761: 1756: 1745: 1739: 1738: 1733: 1722: 1704: 1700: 1698: 1697: 1692: 1687: 1686: 1681: 1670: 1664: 1663: 1658: 1647: 1637: 1635: 1629: 1627: 1618: 1614: 1610: 1606: 1603: 1596: 1589: 1585: 1581: 1574: 1570: 1566: 1563:The three lines 1562: 1560: 1559: 1554: 1549: 1548: 1543: 1532: 1526: 1525: 1520: 1509: 1499: 1497: 1496: 1491: 1489: 1488: 1483: 1472: 1466: 1465: 1460: 1449: 1433: 1429: 1425: 1417: 1413: 1409: 1405: 1401: 1397: 1393: 1389: 1385: 1368: 1364: 1360: 1356: 1352: 1348: 1255: 1253: 1251: 1250: 1247: 1244: 1237: 1235: 1234: 1231: 1228: 1221: 1219: 1218: 1215: 1212: 1205: 1203: 1202: 1199: 1196: 1189: 1187: 1186: 1183: 1180: 1172: 1169: 1167: 1166: 1163: 1160: 1153: 1151: 1150: 1147: 1144: 1137: 1135: 1134: 1131: 1128: 1121: 1119: 1118: 1115: 1112: 1104: 1102: 1101: 1098: 1095: 1074:Underwood Dudley 1059: 1055: 1051: 1044: 1040: 1036: 1032: 1028: 1024: 1023: 1022: 1016: 1015: 1007: 995: 984: 970: 944: 932: 925:rational numbers 910: 906: 902: 894: 893: 891: 890: 885: 882: 881: 872:. In contrast, 871: 868:does not divide 867: 859: 858: 856: 855: 850: 847: 846: 836: 832:positive integer 826: 825: 823: 822: 819: 816: 815: 806: 805: 803: 802: 799: 796: 795: 785: 784: 782: 781: 778: 775: 774: 764: 763: 761: 760: 757: 754: 753: 743: 737: 730: 712: 705: 701: 697: 687: 676: 675: 673: 672: 669: 666: 657: 656: 654: 653: 650: 647: 640: 638: 637: 634: 631: 614: 608: 597: 586: 582: 571: 561: 542: 531: 519: 518: 516: 515: 512: 509: 492: 483: 481: 480: 477: 474: 465: 464: 462: 461: 458: 455: 447: 446: 444: 443: 440: 437: 428: 424: 417: 411: 407: 400:rational numbers 383: 382: 380: 379: 376: 373: 337:cubic polynomial 331: 330: 328: 327: 324: 321: 312: 310: 309: 306: 303: 292: 281: 274: 256:field extensions 89:Angle trisection 83: 82: 80: 79: 76: 73: 59: 58: 56: 55: 52: 49: 21: 4601: 4600: 4596: 4595: 4594: 4592: 4591: 4590: 4561: 4560: 4559: 4554: 4543: 4532: 4530: 4519: 4485:Arabian/Islamic 4473: 4462:numeral systems 4351: 4301: 4271: 4219:Heron's formula 4197: 4179: 4071: 4067:Triangle center 4057:Regular polygon 3934:and definitions 3933: 3927: 3889: 3869: 3859: 3821: 3811: 3801: 3791: 3767: 3757: 3740: 3706: 3677:Theon of Smyrna 3322: 3314: 3309: 3207: 3165: 3143: 3141:Further reading 3138: 3130: 3116:10.2307/2323624 3099: 3091: 3090: 3081: 3066: 3062: 3040: 3039: 3035: 3026: 3024: 3015: 3013: 3009: 2996: 2992: 2984: 2977: 2970: 2969: 2965: 2955: 2953: 2943: 2942: 2938: 2931: 2911: 2910: 2906: 2869: 2868: 2861: 2852: 2848: 2841: 2826: 2824: 2820: 2810: 2808: 2804: 2789: 2784: 2783: 2779: 2773: 2753: 2752: 2745: 2741: 2709: 2701:Pierpont primes 2673: 2663: 2658: 2657: 2655: 2620: 2607: 2597: 2587: 2577: 2566: 2565: 2558:regular polygon 2505: 2498: 2497: 2493:with radius of 2483: 2475: 2432: 2426: 2407: 2328: 2327: 2296: 2295: 2258: 2257: 2256:, from Fact 2) 2219: 2218: 2200: 2197: 2192: 2191: 2189: 2184: 2174: 2170: 2166: 2162: 2148: 2144: 2140: 2136: 2132: 2128: 2118: 2114: 2110: 2106: 2102: 2098: 2094: 2090: 2083: 2075: 2071: 2070:(left of point 2067: 2063: 2009: 2003:around 225 BC. 1962: 1949: 1924: 1911: 1897: 1896: 1873: 1870: 1861: 1858: 1849: 1809: 1786: 1778: 1777: 1746: 1723: 1715: 1714: 1702: 1671: 1648: 1640: 1639: 1633: 1631: 1625: 1623: 1621:right triangles 1616: 1612: 1608: 1601: 1594: 1591: 1587: 1583: 1579: 1572: 1568: 1564: 1533: 1510: 1502: 1501: 1473: 1450: 1442: 1441: 1431: 1427: 1423: 1415: 1411: 1407: 1406:, and the line 1403: 1399: 1395: 1391: 1387: 1383: 1366: 1362: 1358: 1354: 1350: 1346: 1304: 1284: 1282:Using a linkage 1276:Huzita's axioms 1268: 1262: 1248: 1245: 1242: 1241: 1239: 1232: 1229: 1226: 1225: 1223: 1216: 1213: 1210: 1209: 1207: 1200: 1197: 1194: 1193: 1191: 1184: 1181: 1178: 1177: 1175: 1174: 1164: 1161: 1158: 1157: 1155: 1148: 1145: 1142: 1141: 1139: 1132: 1129: 1126: 1125: 1123: 1116: 1113: 1110: 1109: 1107: 1099: 1096: 1093: 1092: 1090: 1089: 1086: 1066: 1057: 1053: 1046: 1042: 1038: 1034: 1030: 1026: 1018: 1013: 1011: 1010: 1009: 1005: 1002: 993: 975: 973:field extension 949: 940: 928: 921: 908: 904: 900: 899:if and only if 886: 883: 879: 877: 876: 874: 873: 869: 865: 864:if and only if 851: 848: 844: 842: 841: 839: 838: 834: 820: 817: 813: 812: 811: 809: 808: 800: 797: 793: 791: 790: 788: 787: 779: 776: 772: 770: 769: 767: 766: 758: 755: 751: 749: 748: 746: 745: 739: 732: 726: 719: 710: 703: 699: 693: 678: 670: 667: 664: 663: 661: 659: 651: 648: 645: 644: 642: 635: 632: 629: 628: 626: 624: 610: 599: 588: 587:is a factor of 584: 573: 566: 544: 533: 521: 513: 510: 507: 506: 504: 494: 478: 475: 472: 471: 469: 467: 459: 456: 453: 452: 450: 449: 441: 438: 435: 434: 432: 430: 426: 419: 413: 409: 403: 377: 374: 371: 370: 368: 367: 325: 322: 317: 316: 314: 307: 304: 299: 298: 296: 294: 287: 276: 270: 264:Évariste Galois 226: 170:and a compass, 146: 77: 74: 69: 68: 66: 61: 53: 50: 47: 46: 44: 39: 28: 23: 22: 15: 12: 11: 5: 4599: 4597: 4589: 4588: 4583: 4578: 4573: 4563: 4562: 4556: 4555: 4528: 4525: 4524: 4521: 4520: 4518: 4517: 4512: 4507: 4502: 4497: 4492: 4487: 4481: 4479: 4478:Other cultures 4475: 4474: 4472: 4471: 4470: 4469: 4459: 4458: 4457: 4447: 4446: 4445: 4435: 4434: 4433: 4423: 4422: 4421: 4411: 4410: 4409: 4399: 4398: 4397: 4387: 4386: 4385: 4375: 4374: 4373: 4359: 4357: 4353: 4352: 4350: 4349: 4344: 4339: 4334: 4329: 4327:Greek numerals 4324: 4322:Attic numerals 4319: 4313: 4307: 4303: 4302: 4300: 4299: 4294: 4289: 4283: 4281: 4277: 4276: 4273: 4272: 4270: 4269: 4264: 4259: 4254: 4249: 4241: 4236: 4231: 4226: 4221: 4216: 4211: 4205: 4203: 4199: 4198: 4196: 4195: 4189: 4187: 4181: 4180: 4178: 4177: 4172: 4167: 4162: 4157: 4152: 4150:Law of cosines 4147: 4142: 4137: 4132: 4127: 4122: 4117: 4112: 4107: 4102: 4097: 4091: 4089: 4077: 4073: 4072: 4070: 4069: 4064: 4059: 4054: 4049: 4044: 4042:Platonic solid 4039: 4034: 4029: 4024: 4022:Greek numerals 4019: 4014: 4009: 4004: 3999: 3994: 3989: 3988: 3987: 3982: 3972: 3967: 3966: 3965: 3955: 3954: 3953: 3948: 3937: 3935: 3929: 3928: 3926: 3925: 3920: 3919: 3918: 3913: 3908: 3897: 3895: 3891: 3890: 3888: 3887: 3880: 3873: 3863: 3853: 3850:Planisphaerium 3846: 3839: 3832: 3825: 3815: 3805: 3795: 3785: 3778: 3771: 3761: 3751: 3744: 3734: 3727: 3722: 3714: 3712: 3708: 3707: 3705: 3704: 3699: 3694: 3689: 3684: 3679: 3674: 3669: 3664: 3659: 3654: 3649: 3644: 3639: 3634: 3629: 3624: 3619: 3614: 3609: 3604: 3599: 3594: 3589: 3584: 3579: 3574: 3569: 3564: 3559: 3554: 3549: 3544: 3539: 3534: 3529: 3524: 3519: 3514: 3509: 3504: 3499: 3494: 3489: 3484: 3479: 3474: 3469: 3464: 3459: 3454: 3449: 3444: 3439: 3434: 3429: 3424: 3419: 3414: 3409: 3404: 3399: 3394: 3389: 3384: 3379: 3374: 3369: 3364: 3359: 3354: 3349: 3344: 3339: 3334: 3328: 3326: 3320:Mathematicians 3316: 3315: 3310: 3308: 3307: 3300: 3293: 3285: 3279: 3278: 3273: 3264: 3252:Trisecting via 3249: 3241:Trisecting via 3238: 3216:Trisecting via 3213: 3206: 3203: 3202: 3201: 3196: 3191: 3186: 3181: 3176: 3171: 3169:MathWorld site 3164: 3163:External links 3161: 3160: 3159: 3142: 3139: 3137: 3136: 3110:(3): 185–194. 3095:(March 1988). 3079: 3060: 3049:(5): 400–405. 3033: 3007: 2990: 2963: 2936: 2929: 2904: 2859: 2846: 2839: 2818: 2777: 2771: 2759:The trisectors 2742: 2740: 2737: 2736: 2735: 2730: 2725: 2720: 2715: 2708: 2705: 2688: 2685: 2680: 2676: 2670: 2666: 2651: 2632: 2627: 2623: 2619: 2614: 2610: 2604: 2600: 2594: 2590: 2584: 2580: 2576: 2573: 2544:cubic equation 2523: 2520: 2515: 2511: 2508: 2482: 2479: 2474: 2471: 2428:Main article: 2425: 2422: 2406: 2403: 2384: 2383: 2371: 2368: 2365: 2362: 2359: 2356: 2353: 2350: 2347: 2344: 2341: 2338: 2335: 2324: 2312: 2309: 2306: 2303: 2292: 2280: 2277: 2274: 2271: 2268: 2265: 2250: 2238: 2235: 2232: 2229: 2226: 2086:. A circle of 2060: 2059: 2048: 2041: 2008: 2005: 1989: 1988: 1977: 1974: 1969: 1965: 1961: 1956: 1952: 1948: 1945: 1942: 1939: 1936: 1931: 1927: 1923: 1918: 1914: 1910: 1907: 1904: 1875: 1874: 1871: 1864: 1862: 1859: 1852: 1848: 1845: 1828: 1822: 1818: 1815: 1812: 1805: 1799: 1795: 1792: 1789: 1765: 1759: 1755: 1752: 1749: 1742: 1736: 1732: 1729: 1726: 1690: 1684: 1680: 1677: 1674: 1667: 1661: 1657: 1654: 1651: 1552: 1546: 1542: 1539: 1536: 1529: 1523: 1519: 1516: 1513: 1486: 1482: 1479: 1476: 1469: 1463: 1459: 1456: 1453: 1339: 1338: 1303: 1300: 1283: 1280: 1264:Main article: 1261: 1258: 1085: 1082: 1078:The Trisectors 1065: 1062: 1001: 998: 947:if and only if 920: 917: 903:is a power of 718: 715: 615:then it has a 252:Pierre Wantzel 225: 222: 221: 220: 217: 145: 142: 116:Pierre Wantzel 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4598: 4587: 4584: 4582: 4579: 4577: 4574: 4572: 4569: 4568: 4566: 4553: 4552: 4547: 4540: 4539: 4526: 4516: 4513: 4511: 4508: 4506: 4503: 4501: 4498: 4496: 4493: 4491: 4488: 4486: 4483: 4482: 4480: 4476: 4468: 4465: 4464: 4463: 4460: 4456: 4453: 4452: 4451: 4448: 4444: 4441: 4440: 4439: 4436: 4432: 4429: 4428: 4427: 4424: 4420: 4417: 4416: 4415: 4412: 4408: 4405: 4404: 4403: 4400: 4396: 4393: 4392: 4391: 4388: 4384: 4381: 4380: 4379: 4376: 4372: 4368: 4367: 4366: 4365: 4361: 4360: 4358: 4354: 4348: 4345: 4343: 4340: 4338: 4335: 4333: 4330: 4328: 4325: 4323: 4320: 4318: 4315: 4314: 4311: 4308: 4304: 4298: 4295: 4293: 4290: 4288: 4285: 4284: 4282: 4278: 4268: 4265: 4263: 4260: 4258: 4255: 4253: 4250: 4248: 4247: 4242: 4240: 4237: 4235: 4232: 4230: 4227: 4225: 4222: 4220: 4217: 4215: 4212: 4210: 4207: 4206: 4204: 4200: 4194: 4191: 4190: 4188: 4186: 4182: 4176: 4173: 4171: 4168: 4166: 4163: 4161: 4158: 4156: 4155:Pons asinorum 4153: 4151: 4148: 4146: 4143: 4141: 4138: 4136: 4133: 4131: 4128: 4126: 4125:Hinge theorem 4123: 4121: 4118: 4116: 4113: 4111: 4108: 4106: 4103: 4101: 4098: 4096: 4093: 4092: 4090: 4088: 4087: 4081: 4078: 4074: 4068: 4065: 4063: 4060: 4058: 4055: 4053: 4050: 4048: 4045: 4043: 4040: 4038: 4035: 4033: 4030: 4028: 4025: 4023: 4020: 4018: 4015: 4013: 4010: 4008: 4005: 4003: 4000: 3998: 3995: 3993: 3990: 3986: 3983: 3981: 3978: 3977: 3976: 3973: 3971: 3968: 3964: 3961: 3960: 3959: 3956: 3952: 3949: 3947: 3944: 3943: 3942: 3939: 3938: 3936: 3930: 3924: 3921: 3917: 3914: 3912: 3909: 3907: 3904: 3903: 3902: 3899: 3898: 3896: 3892: 3886: 3885: 3881: 3879: 3878: 3874: 3872: 3868: 3864: 3862: 3858: 3854: 3852: 3851: 3847: 3845: 3844: 3840: 3838: 3837: 3833: 3831: 3830: 3826: 3824: 3820: 3816: 3814: 3810: 3806: 3804: 3800: 3796: 3794: 3792:(Aristarchus) 3790: 3786: 3784: 3783: 3779: 3777: 3776: 3772: 3770: 3766: 3762: 3760: 3756: 3752: 3750: 3749: 3745: 3743: 3739: 3735: 3733: 3732: 3728: 3726: 3723: 3721: 3720: 3716: 3715: 3713: 3709: 3703: 3700: 3698: 3697:Zeno of Sidon 3695: 3693: 3690: 3688: 3685: 3683: 3680: 3678: 3675: 3673: 3670: 3668: 3665: 3663: 3660: 3658: 3655: 3653: 3650: 3648: 3645: 3643: 3640: 3638: 3635: 3633: 3630: 3628: 3625: 3623: 3620: 3618: 3615: 3613: 3610: 3608: 3605: 3603: 3600: 3598: 3595: 3593: 3590: 3588: 3585: 3583: 3580: 3578: 3575: 3573: 3570: 3568: 3565: 3563: 3560: 3558: 3555: 3553: 3550: 3548: 3545: 3543: 3540: 3538: 3535: 3533: 3530: 3528: 3525: 3523: 3520: 3518: 3515: 3513: 3510: 3508: 3505: 3503: 3500: 3498: 3495: 3493: 3490: 3488: 3485: 3483: 3480: 3478: 3475: 3473: 3470: 3468: 3465: 3463: 3460: 3458: 3455: 3453: 3450: 3448: 3445: 3443: 3440: 3438: 3435: 3433: 3430: 3428: 3425: 3423: 3420: 3418: 3415: 3413: 3410: 3408: 3405: 3403: 3400: 3398: 3395: 3393: 3390: 3388: 3385: 3383: 3380: 3378: 3375: 3373: 3370: 3368: 3365: 3363: 3360: 3358: 3355: 3353: 3350: 3348: 3345: 3343: 3340: 3338: 3335: 3333: 3330: 3329: 3327: 3325: 3321: 3317: 3313: 3306: 3301: 3299: 3294: 3292: 3287: 3286: 3283: 3277: 3274: 3272: 3268: 3265: 3263: 3262: 3258: 3253: 3250: 3248: 3247: 3242: 3239: 3237: 3236: 3231: 3230: 3226: 3221: 3217: 3214: 3212: 3209: 3208: 3204: 3200: 3199:Geometry site 3197: 3195: 3192: 3190: 3187: 3185: 3182: 3180: 3177: 3175: 3172: 3170: 3167: 3166: 3162: 3157: 3153: 3149: 3145: 3144: 3140: 3129: 3125: 3121: 3117: 3113: 3109: 3105: 3098: 3094: 3088: 3086: 3084: 3080: 3076: 3072: 3071: 3064: 3061: 3056: 3052: 3048: 3044: 3037: 3034: 3022: 3018: 3011: 3008: 3004: 3000: 2994: 2991: 2983: 2976: 2975: 2967: 2964: 2951: 2947: 2940: 2937: 2932: 2926: 2922: 2921: 2919:Galois Theory 2918: 2914: 2908: 2905: 2901: 2897: 2893: 2889: 2885: 2881: 2877: 2873: 2866: 2864: 2860: 2856: 2850: 2847: 2842: 2840:9780387754802 2836: 2832: 2831: 2822: 2819: 2803: 2799: 2795: 2788: 2781: 2778: 2774: 2768: 2764: 2760: 2756: 2750: 2748: 2744: 2738: 2734: 2731: 2729: 2726: 2724: 2721: 2719: 2716: 2714: 2711: 2710: 2706: 2704: 2702: 2686: 2683: 2678: 2674: 2668: 2664: 2654: 2650: 2646: 2630: 2625: 2621: 2617: 2612: 2608: 2602: 2598: 2592: 2588: 2582: 2578: 2574: 2571: 2563: 2559: 2554: 2552: 2549: 2545: 2537: 2521: 2518: 2509: 2506: 2496: 2492: 2487: 2480: 2478: 2472: 2470: 2468: 2462: 2460: 2456: 2451: 2447: 2445: 2436: 2431: 2423: 2421: 2417: 2414: 2413: 2405:With a string 2404: 2402: 2400: 2396: 2391: 2389: 2369: 2366: 2363: 2360: 2357: 2354: 2351: 2348: 2345: 2342: 2339: 2336: 2333: 2325: 2310: 2307: 2304: 2301: 2293: 2278: 2275: 2272: 2269: 2266: 2263: 2255: 2251: 2236: 2233: 2230: 2227: 2224: 2216: 2215: 2214: 2212: 2208: 2195: 2187: 2182: 2178: 2160: 2156: 2154: 2125: 2121: 2089: 2081: 2057: 2053: 2049: 2046: 2042: 2039: 2038: 2037: 2034: 2032: 2028: 2027: 2022: 2013: 2006: 2004: 2002: 1998: 1994: 1975: 1967: 1963: 1959: 1954: 1950: 1946: 1940: 1937: 1929: 1925: 1921: 1916: 1912: 1905: 1902: 1895: 1894: 1893: 1892: 1888: 1884: 1880: 1868: 1863: 1856: 1851: 1846: 1844: 1842: 1826: 1820: 1816: 1813: 1810: 1803: 1797: 1793: 1790: 1787: 1776:One has also 1763: 1757: 1753: 1750: 1747: 1740: 1734: 1730: 1727: 1724: 1712: 1708: 1688: 1682: 1678: 1675: 1672: 1665: 1659: 1655: 1652: 1649: 1622: 1605: 1597: 1578: 1577:line segments 1550: 1544: 1540: 1537: 1534: 1527: 1521: 1517: 1514: 1511: 1484: 1480: 1477: 1474: 1467: 1461: 1457: 1454: 1451: 1439: 1435: 1421: 1381: 1377: 1376: 1370: 1344: 1336: 1331: 1330: 1329: 1327: 1323: 1322: 1318:published in 1317: 1308: 1301: 1299: 1297: 1288: 1281: 1279: 1277: 1273: 1267: 1260:Using origami 1259: 1257: 1171: 1083: 1081: 1079: 1075: 1069: 1064:Other methods 1063: 1061: 1049: 1021: 999: 997: 991: 986: 982: 978: 974: 968: 964: 960: 956: 952: 948: 943: 938: 934: 931: 926: 918: 916: 914: 913:Fermat primes 898: 897:constructible 889: 863: 854: 833: 828: 742: 736: 729: 724: 723:constructible 716: 714: 707: 696: 691: 685: 681: 622: 618: 617:rational root 613: 606: 602: 595: 591: 580: 576: 572:is a root of 569: 563: 559: 555: 551: 547: 540: 536: 529: 525: 502: 498: 491: 487: 422: 416: 406: 401: 396: 394: 393:constructible 390: 386: 365: 361: 357: 353: 349: 348:constructible 345: 340: 338: 333: 320: 302: 293: =  291: 285: 280: 273: 267: 265: 261: 260:Galois theory 257: 253: 245: 238: 234: 230: 223: 218: 215: 214: 213: 211: 208:Construct an 206: 204: 200: 195: 193: 189: 185: 184:bisect angles 181: 177: 173: 169: 161: 158: 154: 150: 143: 141: 139: 134: 132: 127: 125: 121: 117: 112: 110: 106: 102: 98: 94: 90: 72: 64: 42: 37: 32: 19: 4542: 4529: 4371:Thomas Heath 4362: 4245: 4229:Law of sines 4085: 4017:Golden ratio 3905: 3882: 3875: 3866: 3860:(Theodosius) 3856: 3848: 3841: 3834: 3827: 3818: 3808: 3802:(Hipparchus) 3798: 3788: 3780: 3773: 3764: 3754: 3746: 3741:(Apollonius) 3737: 3729: 3717: 3692:Zeno of Elea 3452:Eratosthenes 3442:Dionysodorus 3255: 3244: 3233: 3223: 3179:Some history 3147: 3128:the original 3107: 3103: 3074: 3068: 3063: 3046: 3042: 3036: 3025:. Retrieved 3021:the original 3010: 2998: 2993: 2973: 2966: 2954:. Retrieved 2950:the original 2939: 2920: 2917: 2913:Stewart, Ian 2907: 2899: 2879: 2875: 2854: 2849: 2829: 2821: 2809:. Retrieved 2797: 2793: 2780: 2758: 2652: 2648: 2644: 2561: 2555: 2541: 2495:circumcircle 2476: 2463: 2452: 2448: 2441: 2418: 2410: 2408: 2392: 2385: 2253: 2209: 2193: 2185: 2179: 2157: 2127:. A radius 2123: 2119: 2061: 2044: 2035: 2030: 2024: 2018: 1996: 1990: 1879:trisectrices 1876: 1709:, since all 1599: 1592: 1437: 1436: 1390:on the line 1373: 1371: 1340: 1333: 1325: 1319: 1313: 1293: 1269: 1087: 1077: 1070: 1067: 1047: 1019: 1003: 987: 980: 976: 966: 962: 958: 954: 950: 941: 935: 929: 922: 896: 887: 861: 852: 829: 740: 734: 727: 720: 708: 694: 683: 679: 611: 604: 600: 593: 589: 578: 574: 567: 564: 557: 553: 549: 545: 538: 534: 527: 523: 500: 496: 489: 485: 425:. Note that 420: 414: 404: 397: 366:. The angle 364:power of two 341: 334: 318: 300: 289: 278: 271: 268: 250: 239:is un-marked 237:straightedge 207: 196: 168:straightedge 165: 135: 128: 113: 105:straightedge 88: 87: 70: 62: 40: 4438:mathematics 4246:Arithmetica 3843:Ostomachion 3812:(Autolycus) 3731:Arithmetica 3507:Hippocrates 3437:Dinostratus 3422:Dicaearchus 3352:Aristarchus 3232:; see also 2882:: 320–323. 2800:: 366–372. 2534:, based on 2390:is proved. 2326:Therefore, 2023:, called a 1885:, given in 862:trisectible 690:irreducible 598:. Because 124:right angle 95:of ancient 4565:Categories 4490:Babylonian 4390:arithmetic 4356:History of 4185:Apollonius 3870:(Menelaus) 3829:On Spirals 3748:Catoptrics 3687:Xenocrates 3682:Thymaridas 3667:Theodosius 3652:Theaetetus 3632:Simplicius 3622:Pythagoras 3607:Posidonius 3592:Philonides 3552:Nicomachus 3547:Metrodorus 3537:Menaechmus 3492:Hipparchus 3482:Heliodorus 3432:Diophantus 3417:Democritus 3397:Chrysippus 3367:Archimedes 3362:Apollonius 3332:Anaxagoras 3324:(timeline) 3235:Trisectrix 3027:2013-11-04 2739:References 2733:Trisectrix 2455:set square 2181:Conclusion 2159:Hypothesis 2021:Archimedes 2001:On Spirals 619:. By the 352:polynomial 219:a compass. 182:lines, to 120:impossible 18:Trisection 3951:Inscribed 3711:Treatises 3702:Zenodorus 3662:Theodorus 3637:Sosigenes 3582:Philolaus 3567:Oenopides 3562:Nicoteles 3557:Nicomedes 3517:Hypsicles 3412:Ctesibius 3402:Cleomedes 3387:Callippus 3372:Autolycus 3357:Aristotle 3337:Anthemius 3269:on using 3261:Nicomedes 2896:126351853 2713:Bisection 2618:⋯ 2514:¯ 2395:framework 2153:isosceles 2031:un-marked 1960:− 1821:^ 1798:^ 1758:^ 1735:^ 1707:isosceles 1683:^ 1660:^ 1545:^ 1522:^ 1485:^ 1462:^ 1324:his work 1314:In 1932, 570:= cos 20° 532:. Define 423:= cos 20° 346:that is 288:cos  277:cos  247:Compasses 157:arbitrary 153:Bisection 114:In 1837, 4515:Japanese 4500:Egyptian 4443:timeline 4431:timeline 4419:timeline 4414:geometry 4407:timeline 4402:calculus 4395:timeline 4383:timeline 4086:Elements 3932:Concepts 3894:Problems 3867:Spherics 3857:Spherics 3822:(Euclid) 3768:(Euclid) 3765:Elements 3758:(Euclid) 3719:Almagest 3627:Serenus 3602:Porphyry 3542:Menelaus 3497:Hippasus 3472:Eutocius 3447:Domninus 3342:Archytas 3257:Conchoid 3220:Archived 3014:Jim Loy 2982:Archived 2956:30 March 2915:(1989). 2802:Archived 2757:(1994), 2707:See also 2491:heptagon 2444:tomahawk 2386:and the 2183:: angle 2161:: Given 1991:and the 1711:radiuses 1607:, where 1372:Now the 1296:linkages 692:over by 313:− 3 cos 188:polygons 180:parallel 4495:Chinese 4450:numbers 4378:algebra 4306:Related 4280:Centers 4076:Results 3946:Central 3617:Ptolemy 3612:Proclus 3577:Perseus 3532:Marinus 3512:Hypatia 3502:Hippias 3477:Geminus 3467:Eudoxus 3457:Eudemus 3427:Diocles 3271:origami 3225:limacon 3124:2323624 2811:3 March 2645:r, s, k 2388:theorem 2204:⁠ 2190:⁠ 1889:by the 1590:. Thus 1272:origami 1252:⁠ 1240:⁠ 1236:⁠ 1224:⁠ 1220:⁠ 1208:⁠ 1204:⁠ 1192:⁠ 1188:⁠ 1176:⁠ 1168:⁠ 1156:⁠ 1152:⁠ 1140:⁠ 1136:⁠ 1124:⁠ 1120:⁠ 1108:⁠ 1103:⁠ 1091:⁠ 1017:⁄ 937:Theorem 892:⁠ 875:⁠ 857:⁠ 840:⁠ 824:⁠ 810:⁠ 804:⁠ 789:⁠ 783:⁠ 768:⁠ 762:⁠ 747:⁠ 700:cos 20° 674:⁠ 662:⁠ 655:⁠ 643:⁠ 639:⁠ 627:⁠ 585:cos 20° 530:− 1 = 0 520:. Thus 517:⁠ 505:⁠ 493:and so 482:⁠ 470:⁠ 463:⁠ 451:⁠ 445:⁠ 433:⁠ 427:cos 60° 410:cos 20° 389:degrees 385:radians 381:⁠ 369:⁠ 329:⁠ 315:⁠ 311:⁠ 297:⁠ 192:squares 109:compass 81:⁠ 67:⁠ 57:⁠ 45:⁠ 4510:Indian 4287:Cyrene 3819:Optics 3738:Conics 3657:Theano 3647:Thales 3642:Sporus 3587:Philon 3572:Pappus 3462:Euclid 3392:Carpus 3382:Bryson 3229:Pascal 3154:  3122:  2927:  2894:  2837:  2769:  2699:(i.e. 2643:where 2173:, and 2139:, and 2088:radius 1571:, and 1438:Proof: 1343:circle 965:− cos( 830:For a 725:angle 565:Since 295:4 cos 233:Rulers 201:, and 160:angles 107:and a 4505:Incan 4426:logic 4202:Other 3970:Chord 3963:Axiom 3941:Angle 3597:Plato 3487:Heron 3407:Conon 3131:(PDF) 3120:JSTOR 3100:(PDF) 2985:(PDF) 2978:(PDF) 2892:S2CID 2805:(PDF) 2796:. 1. 2790:(PDF) 2560:with 2551:roots 2211:Proof 2054:will 1634:' 1626:' 1602:' 1595:' 1335:hook. 990:proof 979:(cos( 957:) = 4 625:±1, ± 552:) = 8 412:over 356:field 210:angle 101:angle 43:> 4467:list 3755:Data 3527:Leon 3377:Bion 3254:the 3152:ISBN 2958:2012 2925:ISBN 2835:ISBN 2813:2014 2767:ISBN 2548:real 2151:are 2147:and 2062:Let 1630:and 1615:and 1582:and 1500:and 1365:and 988:The 468:cos 431:cos 387:(60 176:line 4369:by 4083:In 3259:of 3243:an 3227:of 3112:doi 3051:doi 2884:doi 2469:). 2442:A " 2397:of 2279:180 2254:BCD 2237:180 2149:BCD 2145:ABC 2080:ray 2045:and 1997:any 1705:is 1703:PAE 1380:leg 1254:+ ⋯ 1173:or 1170:+ ⋯ 1165:256 1050:= 3 994:60° 961:− 3 927:by 895:is 860:is 711:60° 688:is 658:or 641:, ± 560:− 1 556:− 6 526:− 6 499:− 3 488:− 3 484:= 4 402:by 155:of 4567:: 3118:. 3108:95 3106:. 3102:. 3082:^ 3047:94 3045:. 2898:. 2890:. 2880:92 2878:. 2874:. 2862:^ 2792:. 2765:, 2761:, 2746:^ 2556:A 2553:. 2542:A 2461:. 2291:°. 2249:°. 2213:: 2207:. 2188:= 2175:CD 2171:BC 2169:, 2167:AB 2163:AD 2141:CD 2137:BC 2135:, 2133:AB 2129:BC 2124:AB 2122:= 2120:CD 2091:AB 1632:PD 1624:PD 1617:SE 1613:PD 1609:D' 1598:= 1593:SD 1588:SE 1584:PA 1580:OP 1573:AE 1569:PD 1567:, 1565:OS 1434:. 1428:SE 1412:SE 1408:PD 1404:PE 1392:PC 1369:. 1274:. 1249:16 1238:− 1222:+ 1206:− 1190:= 1154:+ 1149:64 1138:+ 1133:16 1122:+ 1105:= 1080:. 1060:. 985:. 983:)) 933:. 915:. 827:. 792:15 706:. 562:. 503:= 448:= 429:= 332:. 126:. 111:. 65:= 48:3π 3304:e 3297:t 3290:v 3218:( 3158:. 3114:: 3057:. 3053:: 3030:. 2960:. 2933:. 2886:: 2844:. 2815:. 2798:2 2687:1 2684:+ 2679:u 2675:3 2669:t 2665:2 2653:i 2649:p 2631:, 2626:k 2622:p 2613:2 2609:p 2603:1 2599:p 2593:s 2589:3 2583:r 2579:2 2575:= 2572:n 2562:n 2522:6 2519:= 2510:A 2507:O 2465:( 2382:. 2370:b 2367:3 2364:= 2361:b 2358:+ 2355:b 2352:2 2349:= 2346:b 2343:+ 2340:c 2337:= 2334:a 2323:. 2311:b 2308:2 2305:= 2302:c 2276:= 2273:b 2270:2 2267:+ 2264:e 2234:= 2231:c 2228:+ 2225:e 2201:3 2198:/ 2194:a 2186:b 2115:D 2111:C 2107:l 2103:A 2099:B 2095:A 2084:B 2076:A 2072:B 2068:a 2064:l 2058:. 2047:, 1976:, 1973:) 1968:2 1964:y 1955:2 1951:x 1947:3 1944:( 1941:a 1938:= 1935:) 1930:2 1926:y 1922:+ 1917:2 1913:x 1909:( 1906:x 1903:2 1827:, 1817:D 1814:P 1811:E 1804:= 1794:P 1791:E 1788:A 1764:. 1754:P 1751:E 1748:A 1741:= 1731:E 1728:P 1725:A 1689:, 1679:S 1676:P 1673:D 1666:= 1656:D 1653:P 1650:E 1636:E 1628:S 1604:E 1600:D 1551:. 1541:D 1538:P 1535:E 1528:= 1518:E 1515:P 1512:B 1481:S 1478:P 1475:D 1468:= 1458:D 1455:P 1452:E 1432:A 1424:E 1416:P 1400:A 1396:E 1388:S 1384:O 1367:O 1363:A 1359:P 1355:B 1351:A 1347:P 1337:" 1332:" 1246:/ 1243:1 1233:8 1230:/ 1227:1 1217:4 1214:/ 1211:1 1201:2 1198:/ 1195:1 1185:3 1182:/ 1179:1 1162:/ 1159:1 1146:/ 1143:1 1130:/ 1127:1 1117:4 1114:/ 1111:1 1100:3 1097:/ 1094:1 1058:3 1054:N 1048:n 1043:N 1039:2 1035:2 1031:n 1027:n 1020:N 1014:π 1012:2 1006:N 981:θ 977:Q 969:) 967:θ 963:t 959:t 955:t 953:( 951:q 942:θ 930:Q 909:2 905:2 901:N 888:N 884:/ 880:π 878:2 870:N 866:3 853:N 849:/ 845:π 843:2 835:N 821:7 818:/ 814:π 801:7 798:/ 794:π 780:7 777:/ 773:π 771:3 759:7 756:/ 752:π 750:3 741:θ 735:θ 733:3 728:θ 704:3 695:Q 686:) 684:t 682:( 680:p 671:8 668:/ 665:1 660:± 652:4 649:/ 646:1 636:2 633:/ 630:1 612:Q 607:) 605:t 603:( 601:p 596:) 594:t 592:( 590:p 581:) 579:t 577:( 575:p 568:x 558:t 554:t 550:t 548:( 546:p 541:) 539:t 537:( 535:p 528:x 524:x 522:8 514:2 511:/ 508:1 501:x 497:x 495:4 490:x 486:x 479:3 476:/ 473:π 460:2 457:/ 454:1 442:3 439:/ 436:π 421:x 415:Q 405:Q 378:3 375:/ 372:π 326:3 323:/ 319:θ 308:3 305:/ 301:θ 290:θ 279:θ 272:θ 84:. 78:3 75:/ 71:θ 63:φ 54:4 51:/ 41:θ 20:)

Index

Trisection

neusis construction
straightedge and compass construction
Greek mathematics
angle
straightedge
compass
Pierre Wantzel
impossible
right angle
neusis construction
pseudomathematical

Bisection
arbitrary
angles
straightedge
Greek mathematicians
line
parallel
bisect angles
polygons
squares
doubling the cube
squaring the circle
angle

Rulers
straightedge

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