Perimeter
From AoPSWiki
Definition
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.
Formulas
- 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.
