Question

Angles A and B are complementary. The measure of angle A is yº. What is the measure of angle B?

Answer 1

Answer:

D, $(90-y)$ degrees

Step-by-step explanation:

Complementary angles are angles that add up to 90 degrees. Since angle A and angle B are complementary, they add up to 90. Since the value of angle A is y degrees, we can substitute y into the equation to get

$y+B=90$

To get the measure of angle B, we must isolate B.

To isolate B, we have to remove every term from its side.

The only term on the side that B is on other than B is y. To remove y from the left side, we must subtract y from both sides. Doing this will result in the equation:

$B=90-y$

The only answer option that meets this criteria is D.