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: $2(l+w)$, where $l$ is the length and $w$ is the width.
  • Square: $4s$, where $s$ is the side length. <follows from rectangle>
  • Circle - $2\pi r$, where $r$ is the radius.
  • Polygon with $q$ sides: $\sum_{z=1}^{q} a_z$, where $a_i$ are the lengths of the sides of the polygon.

Introductory Example Problems