Angle
In geometry, there are pairs angles having a special relationship with each other, making them interesting and convenient.There is a pair of angles called complementary angles to which the sum of their measure (wideness) is equal to one right angle (which is equal to  turn, 90°, or  radians). Supplementary angles are also two angles, this time their combined measure is a straight angle ( turn, 180°, or  radians). Two angles that total to a full angle ( turn, 360°, or  radians) are referred to as explementary or conjugate angles.