Ohio Assessments for Educators (OAE) Mathematics Practice Exam 2025 - Free Practice Questions and Study Guide

Complementary angles are specifically defined as two angles whose measures add up to 90 degrees. This means that when you have two angles, if you take the measure of one angle and add it to the measure of the other angle, the sum will be exactly 90 degrees. This definition is foundational in geometry and is used frequently in various mathematical problems and applications, particularly in trigonometry and when dealing with right angles.

For additional context regarding the other definitions: supplementary angles are those that add up to 180 degrees, which is different from complementary angles; congruence refers to angles that have the same measure, which is not a requirement for angles to be complementary; and the term supplementary itself describes a different relationship between angles. Thus, the defining characteristic of complementary angles is their specific sum of 90 degrees.