Question

In an isosceles triangle, the ratio of the measure of the base angle to that of the vertex angle is 2: 1, what is the measure of the vertex angle?

(A) 18 (B) 24 (C) 36 (D) 48 (5) 72

Answer 1

2x + 2x + x = 180

5x = 180

x = 36°

The correct answer is C.