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Hendecagon - Simple English Wikipedia, the free encyclopedia

From Simple English Wikipedia, the free encyclopedia

A hendecagon or undecagon or 11-gon is a shape with 11 sides and 11 corners.

Regular hendecagon

All sides of a regular hendecagon are the same length. Each corner is 147.27°. All corners added together equal 1619.97°.

The amount of space a regular hendecagon takes up is

$\alpha ={\frac {(n-2)}{n}}\cdot 180^{\circ }={\frac {9}{11}}\cdot 180^{\circ }\approx 147{,}273^{\circ }$

$A={\frac {11}{4}}a^{2}\cot {\frac {\pi }{11}}\approx 9,36564a^{2}\,$

a is the length of one of its sides.

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v t e Polygons
Special cases, including regular polygons with their own names, in parentheses List of polygons by number of sides
1–10 sides	Henagon Digon Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon
11–20 sides	Hendecagon Dodecagon Tridecagon Tetradecagon Pentadecagon Hexadecagon Heptadecagon Octadecagon Enneadecagon Icosagon
21–30 sides	Icosihenagon (21) Icosidigon (22) Icosikaitrigon (23) Icosikaitetragon (24) Icosipentagon (25) Icosihexagon (26) Icosikaiheptagon (27) Icosioctagon (28) Icosikaienneagon (29) Triacontagon (30)
31–50 sides	Triacontadigon (32) Triacontatetragon (34) Tetracontagon (40) Tetracontadigon (42) Tetracontaoctagon (48) Pentacontagon (50)
51–100 sides (selected)	Hexacontagon (60) Hexacontatetragon (64) Heptacontagon (70) Octacontagon (80) Enneacontagon (90) Enneacontahexagon (96) Hectogon (100)
>100 sides	120-gon 257-gon 360-gon Chiliagon (1,000) Myriagon (10,000) 65537-gon Apeirogon (∞)
Star polygons (5–12 sides)	Pentagram Hexagram Heptagram Octagram Enneagram Decagram Hendecagram Dodecagram
Triangles	Equilateral triangle Isosceles triangle Scalene triangle Right triangle Acute and obtuse triangles
Quadrilaterals	Square Rectangle Rhombus Parallelogram Trapezoid Kite Antiparallelogram

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