The angles of an equilateral triangle are congruent. if x represents the measure of one angle of an equilateral triangle, which equation represents the sum of the angle measures of the triangle ?

1. x + x= 90%
2.x + x + x = 90%
3.x + x = 180%
4.x + x + x = 180%

4) x + x + x = 180°

An equilateral triangle has three sides of equal length. Its interior angles are also equal. Since interior angles of a triangle should sum up to 180°, then each angle is 60°, making each angle congruent with one another.

So if x is equal to one angle and triangles have three angles then, 

x + x + x = 180°

or 3x = 180°