ABC is an isosceles triangle with vertex angle C. if m<C=0,then find m<A
A. 70
B. 100
C. 40
D. 60
Since triangle ABC is isosceles, the base angles A and B are congruent. Since the vertex angle C is 0, the base angles A and B must add up to 180 degrees.
Let x be the measure of angle A (and angle B).
x + x + 0 = 180
2x = 180
x = 90
Therefore, m<A = 90 degrees.
Answer: D. 60