Similar Triangles | KS3-KS4 Missing Lengths and Shadow Problems

UK KS3-KS4

Recognise similar triangles, match vertices and calculate missing lengths. Apply proportional reasoning to shadows, with explicit measurement assumptions. Includes homework and worked answers.

WHAT IS INCLUDED

• 16 pages in colour and monochrome, each in A4 and US Letter (four PDFs with matching teaching content).
• 11 editable PowerPoint teaching slides with teacher notes and editable diagrams.
• Readiness check, worked models, classroom practice and reasoning.
• Separate homework, an exit check and a reference summary.
• Worked answers, teaching guidance and editable question text.

SCOPE AND USE
Pupils should know triangle angles sum to 180°, multiply/divide decimals, and use simple ratios. Scale-factor language is introduced here; the separate scale-factor pack is not required. Trigonometric ratios and congruence proofs are outside scope.
Designed for two adaptable lessons; timing depends on pupils’ prior understanding. Diagrams are illustrative, not to scale. No ruler-measuring template or external website is needed. Download the ZIP and extract it before opening the files. A PDF reader and PowerPoint-compatible software are needed; slide appearance may vary in other applications.

LICENCE AND SUPPORT
For one purchasing teacher and the pupils they teach, including secure classroom sharing. Classroom adaptation is allowed; public redistribution and resale are not. Questions or corrections: support@openlatitude.net. Please omit pupil-identifying details. See the preview for actual pupil pages and an answer extract.