Triangle ABC is isosceles with angle B congruent to angle C. The measure of angle C is five times the measure of angle A. What is the number of degrees in the measure of angle B?
A + B + C = 180
Let A = x
B = C = 5x
So
x + 5x + 5x = 180
11x = 180
x = 180 / 11
B = 5 (180 / 11) ≈ 81.81°