Definition

Supplementary Angles

Two angles are supplementary if the sum of their measures equals 180°180°. When two angles are supplementary, each angle is called the supplement of the other. For example, angles measuring 148°148° and 32°32° are supplementary because 148+32=180148 + 32 = 180. This property provides a useful relationship: if xx and yy represent the measures of two supplementary angles, then:

x+y=180x + y = 180

This equation can be paired with a second relationship between the angles to create a system of equations for solving angle problems.

0

1

Updated 2026-04-29

Contributors are:

Who are from:

Tags

OpenStax

Elementary Algebra @ OpenStax

Ch.5 Systems of Linear Equations - Elementary Algebra @ OpenStax

Algebra

Math

Prealgebra

Intermediate Algebra @ OpenStax

Ch.4 Systems of Linear Equations - Intermediate Algebra @ OpenStax

Related
Learn After