A dodecagon is a plane figure with twelve sides, belonging to a polygon, which is widely used in mathematics and life. The sum of the inner angles of the dodecagon is 1800 degrees, and the sum of the outer angles is 360 degrees.

A dodecagon is a closed figure with twelve equilateral sides, and each plane figure with an internal angle of 150 is called a regular dodecagon. Regular dodecagons and equilateral triangles, or squares and regular hexagons, can be densely laid.