Question

If a BASE angle of an isosceles triangle is 54 degrees, what is the measure of the VERTEX angle? * 54 degrees 72 degrees 108 degrees 126 degrees

Answer 1

In an isosceles triangle the base angles are equal

The sum of angles in a triangle is 180 degrees

the base angle is 54 degress

therefore, let the vertex angle be x

x + 54 + 54 = 180

x + 108 = 180

x = 180 - 108

x = 72 degrees

the answer is 72 degrees