1. In pairs, students are given a pairs of picture cards to classify into examples and counter-examples of Congruent figures:
Examples of pairs of picture that illustrate congruence will have
- Images of the same shape, size, colour & orientation
- Images of the same shape, size & orientation, but different colour
- Images of the same shape, size & colour; but reflected (i.e. flipped vertically/horizontally)
Examples of pairs of pictures that illustrate congruence
- Images of the same shape, colour & orientation, but different sizes
- Images of the same colour, orientation & size, but with slightly different shapes (e.g. right-angled triangle and equilateral triangle that with the same size)
3. Elicit from students what are the characteristics presented in each pair of pictures that help them classify the pictures into the examples and counter-examples.
4. Highlight to students that "Images of the same shape, size & colour; but reflected (i.e. flipped vertically/horizontally)" are also congruent.
- Get students to lay the pictures one on top of another to test if the pictures are of the same shape and same size.
