A whole lesson aimed at KS4 (year 10/11) on proving whether shapes are congruent.The lesson begins with pupils creating a mind map showing all the angle rules they know, and a starter extension. We then discuss what congruency is. I then ask pupils to complete a AFL quiz, where they have to identify the congruent triangles. We then discuss all the rules you can use to prove congruency. Pupils are then asked to complete an AFL whiteboard quiz, asking them to identify which rules could be used to prove congruency. Some GCSE exam problems are then modelled and discussed. Pupils then complete some differentiated GCSE exam questions which can be displayed on the board. Two extension activities have also been provided. (Answers are provided). Pupils are then asked to complete an AFL exit ticket before they pack away. AFL confidence checks throughout.