Topic summary · Foundation · CIE Core
Similar Shapes summary
Similar shapes have the same angles and proportional sides. This Foundation summary explains length scale factors and how to find missing sides; use the worksheet for diagrams and the answers PDF to check every step.
Files: foundation-14 Similar Shapes handout.pdf · foundation-14 Similar Shapes handout answers.pdf · free public downloads · diagrams in the PDFs
Key learning points
- Matching angles are equal; corresponding sides share one scale factor .
- Find by dividing a known image side by the matching object side.
- Missing length = matching length × scale factor (or ÷ if going the other way).
- Similar does not mean congruent — sizes may differ.
Worked example 1 — Missing side
Scale factor ; short side . Matching side?
Working
Multiply corresponding lengths.
Worked example 2 — Area scale factor
Length scale factor . Area SF?
Working
Square the length SF.
Worked example 3 — Volume scale factor
Length scale factor . Volume SF?
Working
Cube the length 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.