Hendecagon
From Wikipedia, the free encyclopedia
In geometry, a hendecagon is an 11-sided polygon. Undecagon is incorrect — the prefix is properly Greek, not Latin. A regular hendecagon has internal angles of 147.272727... degrees. The area of a regular hendecagon with side length a is given by
- <math>A = \frac{11}{4}a^2 \cot \frac{\pi}{11} \simeq 9.36564 a^2.</math>
A regular hendecagon is not constructible with compass and straightedge.
The Canadian dollar coin, the Loonie, is a hendecagon. The interior design of the (US coin) Susan B. Anthony silver dollar is also a hendecagon. The Indian two-rupee coin is also a hendecagon.
| Polygons |
|---|
| Triangle | Quadrilateral | Pentagon | Hexagon | Heptagon | Octagon | Enneagon (Nonagon) | Decagon | Hendecagon | Dodecagon | Triskaidecagon | Pentadecagon | Hexadecagon | Heptadecagon | Enneadecagon | Icosagon | Icosihenagon | Tricontagon | Pentacontagon | Hectagon | Chiliagon | Myriagon |
 | This geometry-related article is a stub. You can help Wikipedia by expanding it. |
