# Dictionary Definition

equilateral adj : having all sides or faces equal

# User Contributed Dictionary

## English

1. Referring to a polygon all of whose sides are of equal length. Not necessarily a regular polygon since the angles can still differ (a regular polygon would also be equiangular).

#### Translations

referring to a polygon all of whose sides are of equal length
• Albanian: barabrinjës
• Czech: rovnostranný
• Finnish: tasasivuinen
• German: gleichseitig
• Hebrew:
• Italian: equilatero
• Lithuanian: lygiakraštis

# Extensive Definition

In geometry, an equilateral polygon is a polygon which has all sides of the same length.
For instance, an equilateral triangle is a triangle of equal edge lengths. All equilateral triangles are similar to each other, and have 60 degree internal angles. Any equilateral quadrilateral is a rhombus, which includes the square. An equilateral polygon which is cyclic (its vertices are on a circle) is a regular polygon. Not all equilateral polygons are convex: all equilateral polygons with more than four sides, such as the pentagon, can be concave.
Viviani's Theorem holds for equilateral polygons:
The sum of distances from a point to the side lines of an equilateral polygon does not depend on the point and is that polygon's invariant.

equilateral in Hebrew: שווה צלעות
equilateral in Italian: poligono equilatero
equilateral in Macedonian: Рамностран многуаголник
equilateral in Polish: Wielokąt foremny
equilateral in Finnish: Tasasivuinen monikulmio
equilateral in Swedish: Liksidig