Supplementary and Complementary Angels

To understand supplementary and complementary angles, first we need to understand the adjacent angles.

                         Adjacent angle

Two angles that have a common vertex and a common side but not overlap, are known as adjacent angles.

   Complementary Angles

When the total of measures of two angles is 90^0, the angles are called Complementary Angles”.

If two complementary angles are adjacent then together they form a right angle. 

In the diagram, one pair of angles is 50⁰ and 40^0, and other pair is 30⁰ and 60^0. 

^{The sum of both pairs are} 90^{0 , so these are complementary angles.}

When two angles are complementary, each angle is said to be complement of the other angle.

Angle 50⁰ is Complement of 40^0, and 40⁰ is Complement of 50^0.

Angle 30⁰ is Complement of 60^0, and 60⁰ is Complement of 30^0.

Supplementary  Angles

When the total of measures of two angles is 180^0, the angles are called “Supplementary’ angles.

If two supplementary angles are adjacent then they will form a straight line.

In the diagram, one pair of angles is 130⁰ and 50^0,
and other pair is 110⁰ and 70^0. so these are supplementary angles.

The sum of both pairs are 180^0,

When two angles are supplementary, each angle is said to be supplement of the other angle.

Angle 130⁰ is supplement of 50^0, and 110⁰ is supplement of 70⁰.

Angle 50⁰ is supplement of 130^0, and 70⁰ is supplement of 110^0.