Draw two figures on graph paper (they do NOT have to be triangles) that are the same shape and size. Draw two different figures on your paper that are the same shape but NOT the same size. Compare and contrast the two pairs for similarities and differences. Be specific with respect to their angle measures and side lengths.
Use these examples to differentiate between congruence and similarity. Think about vocabulary such as dilation, enlarge, shrink, rotation, reflection, and translation and discuss as necessary.
Watch this video to make the connection between congruence and similarity.