Learning pack · Foundation · CIE Core
Similar Shapes
What's in this pack: printable worksheet PDF, matching answers PDF, and slides (Foundation · CIE Core depth). 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.
Resources at the top · full summary · videos with short notes below.
🎒 Resources in this pack
Jump straight to the printable files, or scroll to the summary and videos.
Scaffolded Learning Sheet — attempt the worksheet, then use the Answers for a full written solution.
Lesson slides · narrated video available
Files: foundation-14 Similar Shapes handout.pdf · foundation-14 Similar Shapes handout answers.pdf
Full topic 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.
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.
🎬 Topic videos
Beautiful Trigonometry - Numberphile
Numberphile · 12 min
Enrichment / curiosity clip for Lower Secondary (Numberphile-style). Use for hooks, clubs, or stretch — not core exam content.
The Cosine Rule (1 of 3: Proof of the Formula)
Eddie Woo · 13 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Similar Figures
Eddie Woo · 12 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Congruent Figures (1 of 2: Introduction)
Eddie Woo · 8 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Trigonometry Introduction - Corbettmaths
Corbettmaths · 6 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
SOHCAHTOA Finding a missing length
Maths Genie · 10 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
More Lower Secondary packs
Browse the hub Learning Packs & Summary, or open the compact Similar Shapes summary.