Question

∠A and ​∠B​ are vertical angles with m∠A=x and m∠B=5x−80.

What is m∠A?

Answer 1

Vertical angles are equivalent.

Therefore A=B, which means x = 5x-80.

Solve for x:

x+80=5x
80=4x
20=x

Since A = x, and x=20. A = 20

The measure of angle A is 20 degrees.