A *regular pentagon* is a pentagon that has five sides of equal length. Because each side is of equal length, you can find the perimeter of a regular pentagon by **multiplying the length of one side by five.**

So, let *P* represent the perimeter and *s* represent the side.

*P = 5 x s*

The Pentagon building in Arlington, Virginia is an excellent example of a regular pentagon. Each of the Pentagon's five sides are 921 feet long. You calculate the perimeter of the Pentagon by multiplying 921 feet by 5:

*P = 5 x 921 feet*

*P = 4605 feet*

So, the Pentagon has a perimeter of 4,605 feet.