What do you call two angles whose sum equals 90 degrees?

Two angles whose sum equals 90 degrees are referred to as complementary angles. This definition is fundamental in geometry, distinguishing complementary angles from other types of angle relationships.

For instance, if you have two angles, one measuring 30 degrees and the other measuring 60 degrees, their sum is exactly 90 degrees, confirming that they are complementary. This relationship is commonly utilized in various geometric problems, proofs, and in calculations involving right triangles, where the angles of a right triangle are often considered complementary to one another.

Supplementary angles, on the other hand, are defined as two angles whose sum equals 180 degrees, which is a different relationship entirely. Adjacent angles share a common side and vertex but are not necessarily defined by their sum, while vertical angles are formed by two intersecting lines and are equal in measure, rather than defined by their sum. Understanding the specific definitions and relationships between different types of angles is crucial for solving geometric problems effectively.