Definition

Supplementary Angles

Two angles are supplementary if the sum of their measures equals 180180^{\circ}. When two angles are supplementary, each angle is called the supplement of the other. For example, angles measuring 148148^{\circ} and 3232^{\circ} 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.

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Updated 2026-07-03

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