Answer: If the sum of the measures of two angles is not 90°, then they are not complementary angles.
<u>Step-by-step explanation:</u>
Contrapositive of p → q is ~q → ~p where p is the hypothesis and q is the conclusion.
Hypothesis (p) = Two angles are complementary
~p = Two angles are not complementary
Conclusion (q) = The sum of their measures is 90°
~q = The sum of their measures is not 90°
~ p → ~q = If the sum of the measures of two angles is not 90°,
then they are not complementary angles.