Icosagon
| Regular icosagon | |
|---|---|
A regular icosagon  | |
| Type | Regular polygon | 
| Edges and vertices | 20 | 
| Schläfli symbol | {20}, t{10}, tt{5} | 
| Coxeter–Dynkin diagrams | |
| Symmetry group | Dihedral (D20), order 2×20 | 
| Internal angle (degrees) | 162° | 
| Properties | Convex, cyclic, equilateral, isogonal, isotoxal | 
| Dual polygon | Self | 
In geometry, an icosagon or 20-gon is a twenty-sided polygon. The sum of any icosagon's interior angles is 3240 degrees.