what is the perimeter

The perimeter is the total length of the boundary of a two-dimensional shape. It is the distance around the edge of a shape. The perimeter of a shape is determined by adding the length of all the sides and edges enclosing the shape. The perimeter of a circle or an ellipse is called its circumference. The perimeter of a polygon equals the sum of the lengths of its sides (edges). The perimeter of a regular polygon is equal to the product of the number of sides and the length of one side. The perimeter of a rectangle of width and length equals twice the sum of its width and length. The perimeter has several practical applications, such as calculating the length of fence required to surround a yard or garden, the amount of string wound around a spool, or the distance a wheel/circle will roll in one revolution.