What is the measure of the vertex angle of an isosceles triangle if one measure 65 degrees and its congruent sides are 15cm each? a: 50 b: 60 c: 30 d: 40

I believe the answer is A 

Hello, to answer your question in depth and properly

The answer is A
since base angles of an isosceles triangle are congruent the other base angle is also 65. since the three angles together sum to 180 thst leaves 180-65-65=180-130 = 50 degrees for the vertex angle 

          Signed by, Virtuso Sargedog