# Area of a deltoid

## Description

In geometry, a deltoid, also known as a tricuspoid or Steiner curve, is a hypocycloid of three cusps. In other words, it is the roulette created by a point on the circumference of a circle as it rolls without slipping along the inside of a circle with three times its radius. The area of the deltoid is related to the radius of the rolling circle. (The area of the deltoid is twice that of the rolling circle).

Related formulas## Variables

A_{delt} | Area of the deltoid (m^{2}) |

π | pi |

a | The radius of the rolling circle (m) |