# Equilateral triangle - semiperimeter

## Description

In geometry, an equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each other and are each 60°. It is also a regular polygon, so it is also referred to as a regular triangle.

Semiperimeter is expressed as shown

Related formulas## Variables

s | Semiperimeter (m) |

R | radius of the circumscribed circle (m) |

r | radius of the inscribed circle (m) |