The perimeter of a geometric figure is the distance around the outside of the figure. Perimeter is often denoted by P. The perimeter of a circle is called its circumference.
- Rectangle: , where is the length and is the width.
- Square: , where is the side length. <follows from rectangle>
- Circle - , where is the radius.
- Regular polygon with sides: , where is the side length.
- Polygon with sides: , where are the lengths of the sides of the polygon.