If the sum of the measures of two angles is 180 degrees, what are the two angles called?

1. An angle that makes a straight line measures 180 degrees. 2. Two angles whose measures add up to that same 180 degrees are called supplementary angles. 3. Complementary describes a pair that adds to 90 degrees instead, so it does not fit a 180-degree total. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 9 "Math Models and Geometry", section 9.3 Use Properties of Angles, Triangles, and the Pythagorean Theorem_