What do the following two equations represent?

a = 90°

b = 90°

c = 50°

Step-by-step explanation:

The angle with a measure of 40° and the angle labeled "c" are complementary angles

Complementary angles add up to equal 90°

Thus 40 + c = 90

90 - 40 = 50

Thus c = 50

∠A and the angle with a right angle are supplementary angles

Supplementary angles add up to equal 180°

Thus, ∠a + 90 = 180

180 - 90 = 90

Thus, ∠a = 90

∠a ≅ ∠b because vertical angles

because ∠a = 90°, ∠b also equals 90°