Year 9 · Maths · beta

Geometrical properties: similarity and Pythagoras' theorem

This unit explores the concepts of congruence and similarity, and ways to prove or disprove similarity between shapes. We then explore further properties of triangles with Pythagoras' Theorem.

This is an attributed Oak National Academy lesson sequence, not a completed or academically approved DASKEREL course. Supporting transcripts may depend on video, images, practical equipment or teacher explanation. Follow each lesson’s supervision guidance. For religious education and RSHE, follow the school’s syllabus, policy and safeguarding procedures.

Prior knowledge

  • Recognise right-angled triangles
  • Apply Pythagoras' Theorem to find missing lengths
  • Use ratios in similar shapes

Source curriculum references

  • Use the standard conventions for labelling the sides and angles of triangle ABC, and know and use the criteria for congruence of triangles
  • Apply angle facts, triangle congruence, similarity and properties of quadrilaterals to derive results about angles and sides, including Pythagoras’ Theorem, and use known results to obtain simple proofs
  • Use Pythagoras’ Theorem and trigonometric ratios in similar triangles to solve problems involving right-angled triangles

Oak source metadata. DASKEREL has not independently verified school-level coverage.

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