Which type of angles have a sum of 90 degrees?

Complementary angles are defined as two angles whose measures add up to 90 degrees. This concept is fundamental in geometry, particularly when dealing with right angles and various geometric constructions. For instance, if one angle measures 30 degrees, its complement must measure 60 degrees, since 30 + 60 = 90. This relationship is widely utilized in solving problems involving right triangles and various geometric figures.

In contrast, supplementary angles are pairs of angles that sum to 180 degrees, which does not apply here. Adjacent angles refer to angles that share a common side and vertex but do not necessarily sum to any specific measure. Vertical angles are formed when two lines intersect and are always equal in measure but also do not relate to a sum of 90 degrees. Therefore, the correct identification of complementary angles highlights their unique relationship in terms of their specific sum of 90 degrees.