Hendecagon

A hendecagon, also known as an undecagon, is a polygon with eleven sides and eleven angles. The term comes from the Greek words "hendeca," meaning eleven, and "gonia," meaning angle. In geometry, each interior angle of a regular hendecagon (where all sides and angles are equal) measures approximately 147.27 degrees, and the sum of the interior angles of a hendecagon is 1620 degrees.