Question

What is the measure of angle A?

Answer 1

∠A = 58°

Explanation:

The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.

∠ACD is an exterior angle

∠A and ∠B are the opposite interior angles, thus

∠A + 80 = 138 ( subtract 80 from both sides )

∠A = 58°