Complementary Angles- When the sum of two angles is equal to 90 degrees, they are called complementary angles. (For example, 30 degrees and 60 degrees are complementary angles)
Supplementary Angles-Supplementary angles are those angles that sum up to 180 degrees. (For example, angle 130° and angle 50° are supplementary angles because sum of 130° and 50° is equal to 180°.)
Congruence Postulate- to be congruent if two angles and the side between these two angles of one triangle are congruent to corresponding angles and the included side (side between two angles) of the other triangle
Linear Pairs of Angles-A linear pair of angles is formed when two lines intersect. Two angles are said to be linear if they are adjacent angles formed by two intersecting lines. The measure of a straight angle is 180 degrees, so a linear pair of angles must add up to 180 degrees.