7th Grade · Geometry
Complementary
7.G.B.5
Definition
Two angles whose measures sum to 90°. Each angle is the complement of the other.
Examples
- 55° and 35° sum to 90° — complementary.
- Complement of 30° = 90° - 30° = 60°.
Key rule
Complementary angles don't have to be adjacent — they just need to sum to 90°.
Memory hook
Two angles, add to a right angle.