In this activity pupils start by finding the missing angles and are then tasked with writing a reason for their answer, by using the ‘Build a sentence’ sheet to help them write a completely correct full sentence. After doing some mocks with my GCSE pupils it became clear that they got what was going on, but couldn’t communicate the reason in order to get the C (communication) mark, so I created this. Aimed at KS3, but could be used with Lower ability GCSE pupils or as a refresher for higher pupils who need help with writing reason answers.