What is the sum of the measures of supplementary angles?

Supplementary angles are defined as two angles whose measures add up to 180 degrees. This definition is foundational in geometry and is used in various applications across the subject. When you have a pair of angles that are supplementary, their sum is always consistent and equal to 180 degrees.

For example, if one angle measures 120 degrees, the supplementary angle would measure 60 degrees, since 120 + 60 = 180. This relationship applies to any pair of supplementary angles, making the sum of their measures universally 180 degrees. This will remain true regardless of the individual angle measures as long as they are classified as supplementary.

Understanding this concept is essential for solving problems involving angles in geometry, including those encountered in the Praxis Pennsylvania Grades 4–8 Core Assessment.