Congruence GM3.1 Core Plenary This is a tangram. It is made from 7 shapes. These are labelled A to G. Shapes A and F are congruent. So are shapes E and G. How many different squares can you make? You do not have to use all the pieces, but you cannot use any piece more than once in a single square. How many of the squares are congruent? Here is one square. C D G A F B E Preamble This activity is suitable for pairs, with a whole-class session to compare and discuss results at the end. It could be performed either as an exercise in mental imagery or with the actual tangram pieces, depending on circumstances. Possible content Constructing and recognising congruent shapes; visualising the movement of shapes. Resources Squared paper (or card and scissors if tangrams are to be made). Solution/Notes 8 squares may be made (excluding the original one). Of these, there is one pair of congruent shapes and one quintuplet (group of 5) congruent shapes. A F Original Material © Cambridge University Press 2009 Original Material © Cambridge University Press 2009