| Regular icosagon | |
|---|---|
  A regular icosagon (Second image divided into triangles) |
|
| Edges and vertices | 20 |
| Schläfli symbol | {20} |
| Coxeter–Dynkin diagram |    |
| Symmetry group | Dihedral (D20) |
| Area (with t=edge length) |
  |
| Internal angle (degrees) |
162° |
| Properties | convex, cyclic, equilateral, isogonal, isotoxal |
In geometry, an icosagon is a twenty-sided polygon. The sum of any icosagon's interior angles is 3240 degrees.
One interior angle in a regular icosagon is 162° meaning that one exterior angle would be 18°
The regular icosagon is a constructible polygon, by an edge-bisection of a regular decagon, and can be seen as a truncated decagon.
Uses
The most famous use of an icosagon is the Showcase Showdown wheel on the popular US game show The Price Is Right.
The Globe, the outdoor theater used by William Shakespeare's acting company, was discovered to have been built on an icosagonal foundation when a partial excavation was done in 1989. [1]
As a golygonal path, the swastika is considered to be an irregular icosagon. [1]
Petrie polygons
The regular icosagon is the Petrie polygon for four higher dimensional polytopes, shown in these skew orthogonal projections:
 9-orthoplex (10D) |
 9-cube (10D) |
| 19-simplex (19D) | 11-demicube (11D) |
References
- ^ Weisstein, Eric W., "Icosagon" from MathWorld.
 |
This geometry-related article is a stub. You can help Wikipedia by expanding it. |
|
||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
