What Is an Equilateral Triangle?

What Is an Equilateral Triangle?

An equilateral triangle is a triangle that has three equal angles and three sides the same length.

Note: The lines through the sides of the triangle in the image above indicate they are of equal length. The arcs indicate the angles are equal.

Dictionary Definition

The Merriam-Webster dictionary defines an equilateral triangle as "a triangle in which all three sides are the same length."

Real Examples of Equilateral Triangles

Below are real examples of equilateral triangles.

In each case

  • All 3 sides are the same length.

  • All 3 angles are the same (60°).

Properties of Equilateral Triangles

The Interior Angles of an Equilateral Triangle

Each interior angle of an equilateral triangle is 60°.

The Symmetry of Equilateral Triangles

An equilateral triangle has 3 lines of symmetry.

See Also

What is a triangle? What is an angle? Interior angles of a triangle