Name a pair supplementary angles

http://www.mathsisfun.com/geometry/supplementary-angles.html

To find a pair of supplementary angles, we need to look for two angles whose measures add up to 180 degrees. Here is an example:

Let's say we have Angle A and Angle B. Angle A measures 120 degrees. To find a supplementary angle to Angle A, we subtract its measure from 180 degrees.

180 degrees - 120 degrees = 60 degrees

Therefore, Angle B measures 60 degrees. Angle A (120 degrees) and Angle B (60 degrees) form a pair of supplementary angles because their measures add up to 180 degrees.