Geometry math question

Question

Each base angle of an isosceles triangle is 30 more than twice the measure of the vertex angle. What is the measure of the vertex angle? 

A) 48

B) 24

C) 78

D) 42

Answer 1

Let x = the vertex angle

 

each base angle = 30 + 2x

 

sum of all 3 equals 180

 

x + 2(30 + 2x) = 180

 

5x + 60 = 180

 

5x = 120

 

x =  24

 

answer B