1. The problem is to understand the meaning of "complementary" in mathematics. 2. In mathematics, "complementary" usually refers to two angles whose measures add up to 90 degrees. 3. The formula for complementary angles is: $$\text{Angle}_1 + \text{Angle}_2 = 90^\circ$$ 4. Important rule: If two angles are complementary, knowing one angle allows you to find the other by subtracting from 90 degrees. 5. For example, if one angle is $30^\circ$, the complementary angle is: $$90^\circ - 30^\circ = 60^\circ$$ 6. This concept is often used in geometry and trigonometry to solve problems involving right angles. 7. Summary: Complementary angles sum to 90 degrees, and this relationship helps find unknown angles when one is known.