The question asks: "What are two angles whose sum equals 90 degrees called?"

The correct answer is Complementary. Complementary angles are two angles whose measures add up to 90 degrees.

Would you like further details on complementary angles or how they differ from supplementary or other angle types?

Here are 5 related questions to explore:

1. What are supplementary angles?
2. How do complementary angles appear in geometric problems?
3. Can two complementary angles be equal?
4. What are vertical angles, and how are they related to complementary angles?
5. How are complementary angles used in right-angle triangles?

Tip: A quick way to remember the difference between complementary and supplementary angles is that C comes before S in the alphabet, and 90° (complementary) is smaller than 180° (supplementary).