What are the measures of two complementary angles if the difference in their measures is 18?

Complementary angles = 90°
x= angle 1
(90-x)= angle 2

Subtract the two angles to get the difference between them (18°).

(90-x) - x= 18
combine like terms

90 - 2x= 18
subtract 90 from both sides

-2x= -72
divide both sides by -2

x= 36° angle 1

Substitute answer in to find angle 2:
=90 - x
=90 - 36
=54° angle 2

Hope this helps! :)