What is perimeter?

Perimeter is the distance around the outside of a two-dimensional shape. It is calculated by adding together the lengths of all the sides of the shape.

Perimeter is the distance around the outside of a two-dimensional shape. It is the sum of the lengths of all the sides of the shape. Perimeter is measured in linear units such as inches, centimeters, or meters.

The perimeter of a square is four times the length of one side. The perimeter of a rectangle is twice the length plus twice the width. The perimeter of a triangle is the sum of the lengths of the three sides.

The perimeter of a circle is called its circumference. The circumference of a circle is equal to pi times the diameter of the circle, or pi times twice the radius of the circle.