Angles on Parallel Lines | I Do, We Do, You Do | Year 9 Maths | Print Free

Build confidence with parallel-line angle facts, then challenge pupils to combine them with triangles, algebra and ratio. This editable 96-slide Year 9 maths PowerPoint provides structured modelling, substantial practice and answers in a print-free format. Project the supplied diagrams and let pupils work in exercise books or respond on mini whiteboards.

I DO, WE DO, YOU DO
Three matched I Do / We Do pairs introduce corresponding, alternate and co-interior angles, using different examples and varied diagram orientations. A six-question modelling overview and individual teaching slides provide space for teacher working. Further examples combine angle facts, triangle angles and reflex angles, with worked solutions explaining the steps.

SHARED DIAGRAMS, PLENTIFUL PRACTICE
Four practice pages contain 60 questions:
• 24 questions using an eight-angle diagram, each asking for two unknown angles and justification.
• 12 multi-step questions using two crossing transversals, triangles and twelve labelled angles.
• 12 algebra and ratio problems, including equations on both sides, reverse calculations and linked angle relationships.
• 12 combined triangle and reflex-angle problems.
Large shared diagrams keep the focus on reasoning and calculation without repeatedly copying figures.

ONE-PAGE DIFFERENTIATION
A shared twelve-angle diagram supports six Developing, six Secure and four Greater Depth questions, plus a Super Challenge. Developing combines numerical angle facts; Secure introduces algebra, ratio and reverse problems. Greater Depth asks pupils to prove relationships, explain how changing one angle affects others and justify whether conditions are possible.

The Super Challenge links two equations and asks pupils to find all twelve angles and establish that the solution is unique. Its complete solution is presented on one slide.

CHECK UNDERSTANDING THROUGHOUT
• Six retrieval questions and six prerequisite questions, each with grouped answers.
• Twenty individual AFL questions in a continuous question-and-answer sequence, suitable for mini whiteboards.
• Misconception checks, including whether parallelism can be assumed from a diagram.
• Additional reasoning tasks, a six-mark exam-style question and three exit checks.
• Answers throughout, with worked algebra and explanations for the more demanding tasks.