Icosagon

Regular icosagon
A regular icosagon.
Edges and vertices	20
Schläfli symbol	{20} t{10}
Coxeter–Dynkin diagram
Symmetry group	Dihedral (D20)
Area (with t=edge length)	$A = 5t^2 \cot \frac{\pi}{20}$ $\simeq 31.5688\,t^2.$
Internal angle (degrees)	162°

In geometry, an icosagon is a twenty-sided polygon. The sum of any icosagon's interior angles is 3240 degrees.