What is the name for a figure with twelve sides?

What is the name for a figure with twelve sides? It is a dodecagon. In geometry, a dodecagon is a polygon with twelve straight sides, twelve vertices, and twelve interior angles. The name comes from Greek roots: dōdeka means “twelve,” while gōnia refers to an angle or corner.

A dodecagon can be regular or irregular. In a regular dodecagon, all twelve sides have equal length and all twelve interior angles are equal. Each interior angle measures 150 degrees, and the sum of the interior angles is 1,800 degrees. A regular dodecagon also has twelve lines of symmetry and rotational symmetry of order 12.

The prefix helps distinguish this shape from nearby polygon names: a decagon has ten sides, while a nonagon has nine and an octagon has eight. Do not confuse a dodecagon with a dodecahedron, which is a three-dimensional solid with twelve faces rather than a flat twelve-sided polygon.