# Perimeter

 related topics {math, energy, light} {math, number, function} {area, part, region} {build, building, house} {service, military, aircraft} {war, force, army} {language, word, form}

A perimeter is a path that surrounds an area. The word comes from the Greek peri (around) and meter (measure). The term may be used either for the path or its length - it can be thought of as the length of the outline of a shape. The perimeter of a circular area is called circumference.

## Contents

### Practical uses

Calculating the perimeter has considerable practical applications. The perimeter can be used to calculate the length of fence required to surround a yard or garden. The perimeter of a wheel (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.A perimeter is the boundary of a shape, or the length of that boundary.

### Formulas

Perimeter is about the distance around all of a shape for e.g. circle , the perimeter around a circle is called a circumference . Perimeters for more general shapes can be calculated as any path with $\int_0^Lds$ where L is the length of the path and ds is an infinitesimal line element. Both of these must be replaced with other algebraic forms in order to be solved: an advanced notion of perimeter, which includes hypersurfaces bounding volumes in n-dimensional euclidean spaces can be found in the theory of Caccioppoli sets.