[share]

A perimeter is a path that encompasses/surrounds a two-dimensional shape.
The term may be used either for the path, or its length—in one dimension.
It can be thought of as the length of the outline of a shape.
The perimeter of a circle or ellipse is called its circumference.

Calculating the perimeter has several practical applications.
A calculated perimeter is the length of fence required to surround a yard or garden.
The perimeter of a wheel/circle (its circumference) describes
how far it will roll in one revolution.
Similarly, the amount of string wound around a spool is related to the spool's perimeter;
if the length of the string was exact, it would equal the perimeter.