Dodecagon

A dodecagon or 12-gon is a shape with 12 sides and 12 corners.

 Regular dodecagon 
All sides of a regular dodecagon are the same length. Each corner is 150°. All corners added together equal 1800°.

 Area 
The amount of space a regular dodecagon takes up is

The variable A represents the area, and the variable a represents the apothem.

 Perimeter 
The perimeter of a regular dodecagon is

The variable P represents the perimeter, and the variable s represents one side.

12