The expression $m\angle Q + m\angle P = 90^\circ$ means that the measures of angles $\angle Q$ and $\angle P$ add up to 90°. Therefore, these two angles are complementary angles.

Complementary angles are two angles whose measures sum to $90^\circ$.

Would you like to know more about complementary angles or how this property can be applied in different geometric problems?

Here are five related questions to explore this concept further:

1. If $m\angle Q = 60^\circ$, what is $m\angle P$?
2. Can two obtuse angles be complementary?
3. How are complementary angles used in right triangles?
4. If $\angle Q$ is twice the size of $\angle P$, what are the measures of both angles?
5. Can complementary angles be adjacent?

Tip: In a right triangle, the two non-right angles are always complementary.