Similar shapes
- Find the scale factor.
- Multiply matching lengths.
- Angles stay equal.
Answer: 5 cm with scale factor 2 becomes 10 cm
📐 Geometry & Measures
Similarity
Learn similarity with a GCSE-style explanation, help guide, worked example, practice question and flashcards.
Global XP
Level 10 / 100 XP
1. Explanation
Key idea
- Similarity is part of geometry and appears often in KS3–GCSE maths.
- Similar shapes have equal angles and proportional sides.
- Use the worked model, help guide, interactive question and flashcards to practise similarity until the steps feel automatic.
Real-life examples
- Shopping, sport, travel, science, design and everyday decisions all use this skill.
2. Visual
Similarity learning map
Understand the key idea → follow the help guide → practise a question → check your method → build speed with flashcards.
3. Help guide
How to tackle Similarity
- Learn the rule: Similar shapes have equal angles and proportional sides.
- Worked model: Find the scale factor. Multiply matching lengths. Angles stay equal.
- Try the interactive question without looking at the answer first.
- Use the flashcards to test the rule, the method and a common check.
4. Worked examples
Step-by-step working
5. Interactive questions
Try it yourself
Two similar shapes have scale factor 3. A 4 cm side becomes what?
6. Flashcards
Master quick recall
Flip each card, then choose whether you know it or need more practice.
0 mastered
FrontRule for Similarity
BackSimilar shapes have equal angles and proportional sides.
FrontExample answer: Two similar shapes have scale factor 3. A 4 cm side becomes what?
Back4 × 3 = 12 cm.
FrontCommon check for Similarity
BackCheck units/notation, compare with an estimate, and make sure the answer matches the question.
7. Finish
Complete this topic
When you have read the examples, tried the question and reviewed flashcards, claim your topic completion XP.