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.
Introduce children to concept of supplementary angles
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
Download this geogebra file from this link.
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
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
- What are supplementary pair of angles?
- Is it required for the pair of angles to be adjacent to be supplementary?
- What type of angles form supplementary pair?