E2.3 Compare angles and determine their relative size by matching them and by measuring them using appropriate non-standard units.
Activity 1 : Congruent Angles, or Not?
Look at the angles that are in the Cartesian plane below and answer the following questions without using a measuring tool.
- Are angles 1 and 5 congruent?
- How can you demonstrate this?
- Show the congruence of angles 2 and 3.
- Are the corresponding line segments that form angles 1 and 4 congruent? Explain your answer.
- Are angles 1 and 4 congruent? Explain your reasoning.
(Provide students with a transparency of the blank grid and erasable markers so they can trace certain angles, if necessary.)
Source: translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca).