"Equilateral" redirects here. For other uses, see Equilateral (disambiguation).Equilateral triangleTypeRegular polygonEdges and vertices3Schläfli symbol{3}Coxeter diagramSymmetry groupD3Area{\displaystyle {\tfrac {\sqrt {3}}{4}}a^{2}}Internal angle (degrees)60°

In geometry, an equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°. They are regular polygons, and can therefore also be referred to as regular triangles.

An equilateral triangle is one in which all three sides are congruent (same length). Because it also has the property that all three interior angles are equal, it really the same thing as an equiangular triangle