# Perimeter of a Circle (by the radius)

## Description

A perimeter is a path that surrounds a two-dimensional shape.The perimeter of a circle or ellipse is called its circumference. A circle can be defined as the curve traced out by a point that moves so that its distance from a given point is constant. The length of the circumference of the circle is related to its radius.

Related formulas## Variables

C | circle circumference (m) |

π | pi |

r | circle radius (m) |