Perimeter

A square and an equilateral triangle are both examples of regular polygons. Another method for finding the perimeter of a regular polygon is to multiply the number of sides by the length of one side. Let's revisit Examples 3 and 4 using this second method.
Example 3:	Find the perimeter of a square with each side measuring 2 inches.
Solution:	This regular polygon has 4 sides, each with a length of 2 inches. Thus we get:
	= 4(2 in) = 8 in
Example 4:	Find the perimeter of an equilateral triangle with each side measuring 4 centimeters.
Solution:	This regular polygon has 3 sides, each with a length of 4 centimeters. Thus we get:
	= 3(4 cm) = 12 cm
Example 5:	Find the perimeter of a regular pentagon with each side measuring 3 inches.
Solution:	= 5(3 in) = 15 in
Example 6:	The perimeter of a regular hexagon is 18 centimeters. How long is one side?
Solution:	= 18 cm
	Let  represent the length of one side. A regular hexagon has 6 sides, so we can divide the perimeter by 6 to get the length of one side ().
	= 18 cm ÷ 6
	= 3 cm
Summary:	To find the perimeter of a polygon, take the sum of the length of each side. The formula for perimeter of a rectangle is: . To find the perimeter of a regular polygon, multiply the number of sides by the length of one side.