Hendecagon

A hendecagon or 11-gon is a shape with 11 sides and 11 corners.
Regular hendecagon.
All sides of a regular hendecagon are the same length. Each corner is 147.27°. All corners added together equal 1619.97°.
Area.
The amount of space a regular hendecagon takes up is
"a" is the length of one of its sides.