Tetracontagon

A tetracontagon or 40-gon is a shape with 40 sides and 40 corners.

All sides of a regular tetracontagon are the same length. Each corner is 171°. All corners added together equal 6840°.

The amount of space a regular tetracontagon takes up is

${\displaystyle {\text{Area}}=10\left(1+{\sqrt {5}}+{\sqrt {5+2{\sqrt {5}}}}+{\sqrt {\left(1+{\sqrt {5}}+{\sqrt {5+2{\sqrt {5}}}}\right)^{2}+1}}\right)t^{2}}$

a is the length of one of its sides.