If the sum of two angles is 90 degrees, what type of angles are they?

When the sum of two angles equals 90 degrees, they are defined as complementary angles. This definition means that if you have two angles that, when added together, result in a right angle (90 degrees), they complement each other to form that right angle.

In geometry, complementary angles are particularly significant not just because of their definition but also because they commonly appear in various geometric constructions and proofs. They can be two separate angles, and they do not need to be adjacent to one another; they just need to add up to 90 degrees.

Understanding the concept of complementary angles helps in a variety of mathematical contexts, including trigonometry and the study of shapes, where right angles are a fundamental element.