This is an example of a [b]triangle[/b]. The sum of the angle measures in a triangle is always [math]180^\circ[/math].

This is an [b]equilateral triangle[/b]. Each angle in an equilateral triangle is [math]60^\circ[/math]. The sides are all equal in length. Each side is represented by [i]a[/i] in this diagram.

This is an [b]isosceles triangle[/b]. Two of the angles in an isosceles triangle are equal, and the other one is different. The two sides opposite these two equal angles are also equal to each other.

This is a [b]scalene triangle[/b]. All of the angles are different in a scalene triangle. All of the sides are also unequal.