How are supplementary angles defined?

Supplementary angles are defined specifically as two angles whose measures add up to 180 degrees. This definition stems from the properties of angles in a plane, where a straight angle measures 180 degrees. Therefore, when two angles combine to form a straight angle, they are classified as supplementary.

This concept is useful in various geometric contexts, such as when dealing with parallel lines and transversals, where certain pairs of angles can be identified as supplementary based on their relationships. The notion that supplementary angles are connected to forming a straight line also reinforces their importance in understanding angle relationships in geometry.

It's important to remember that while angles could also be equal or add up to other specific values, these characteristics relate to different classifications of angles and do not pertain to the definition of supplementary angles. Thus, the distinction that supplementary angles specifically total 180 degrees is paramount for correctly defining their relationship.