Supplementary angles

Supplementary angles are two angles with a sum of 180°. A common case is when they lie on the same side of a straight line.

Objectives
Introduce children to concept of supplementary angles

Estimated Time
30 minutes

Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles

Materials/ Resources needed

 * 1. Digital : Computer, geogebra application, projector.
 * 2. Non digital : Worksheet and pencil.
 * 3. Geogebra files : Supplementary angles.ggb

Process (How to do the activity)

 * Prior hands on activity (optional – children can use news paper strips to make angles and place them together and notice if the resulting angle formed is a straight angle).
 * Students should be able to identify the types of angles in the file
 * Let them attempt to join the two angle - They may try by coinciding different points or lines.
 * Ask about the angle formed by joining the two angles
 * Is the straight angle formed parallel to the x-axis.
 * Challenge them to find another way to make a straight angle using the two existing angles.
 * Interchanging the position of the two angles – ask what they notice.
 * If one of the angle is changed will the two together again form supplementary angle.
 * Readjust to make adjacent angles again to notice the resultant angle.
 * Children can be asked to make note of the angle measures for different positions of the slider in the work sheet
 * Ask students if the angles have to be adjacent to be supplementary pairs.
 * Record the values of the two angles and their sum in the worksheet
 * {| class="wikitable"


 * Sl No.
 * Value of slider α
 * Angle ABC
 * Angle DEF
 * Sum

Angle ABC + Angle DEF
 * Is angle ABC supplement of angle DEF
 * }
 * Evaluation at the end of the activity
 * 1) What are supplementary pair of angles?
 * 2) Is it required for the pair of angles to be adjacent to be supplementary?
 * 3) What type of angles form supplementary pair?
 * }
 * Evaluation at the end of the activity
 * 1) What are supplementary pair of angles?
 * 2) Is it required for the pair of angles to be adjacent to be supplementary?
 * 3) What type of angles form supplementary pair?
 * 1) Is it required for the pair of angles to be adjacent to be supplementary?
 * 2) What type of angles form supplementary pair?