Identifying identical triangles was a little bit of a challenge for a few of my 7th grade students. They could correctly identify a property (Angle, Angle, Side), but then would completely disregard the fact that the sides in the two triangles were not corresponding. I want to revisit the concept with these students as a quick review activity even though our lessons have moved on to other topics. To do so, I created a card sort.
In the card sort, each card has a pair of triangles. Students will sort the cards into categories: “Identical”, “Not Identical”, or “Not Enough Information To Tell”. If the triangles are identical, they will be required to identify the property shown. In order to address the fact that students are not looking to see if the sides are corresponding, I will probably require them to use colored dry erase markers to indicate corresponding sides.
I will pair students who did not master the concept with students who did. I think I will implement a strategy that I read about on another blog (I don’t remember which one, only that it was a great idea), in which students within the pairing are required to take turns. The first partner sorts a card into a category. The second partner then either agrees or disagrees with the sorting. If he or she disagrees, he or she can move it but must explain why it is being moved. The second partner then sorts another card and the first partner can agree or disagree.