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Topic summary · IGCSE handout

Similar Shapes 2 summary

Similarity scales lengths by kk, areas by k2k^2, volumes by k3k^3. Matching angles and proportional sides define similarity.

Files: 36_similar_shapes_2_handout.pdf · 36_similar_shapes_2_handout_answers.pdf · free public downloads · diagrams in the PDFs

Key learning points

  • Corresponding angles equal; corresponding sides in the same ratio.
  • Area factor =(length factor)2=(\text{length factor})^2; volume factor cubed.
  • Find missing sides with matching vertices carefully labelled.

Worked example 1 — Area scale factor

Length SF k=3k=3. Area SF?

Working

99

Square kk.

Worked example 2 — Volume scale factor

Length SF k=2k=2. Volume SF?

Working

88

Cube kk.

Worked example 3 — Length from areas

Areas ratio 16:916:9. Length SF?

Working

4:34:3

Square-root of area SF.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.