An angle measures 18° more than the measure of a supplementary angle. What is the measure of each angle?

Supplementary angles are two angles that add up to 180°

The unknown angle is known as x

The second angle, being 18° more than the unknown angle, is x+18

So, the expression can be written as x+x+18=180

Subtract 18 from both sides.

x+x=162

Combine like terms

2x=162

Divide by 2 on both sides

162/2=81

x=81

So, one of the angles is 81°

The other is 99° (because 81+18)