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.