Use a scale factor
- Identify the scale factor.
- Multiply lengths by it.
- For reverse problems, divide by it.
Answer: 4 cm enlarged by scale factor 2.5 becomes 10 cm
⚖️ Ratio, Proportion & Rates
Scale factors
Learn scale factors with a GCSE-style explanation, help guide, worked example, practice question and flashcards.
Global XP
Level 10 / 100 XP
1. Explanation
Key idea
- Scale factors is part of ratio & proportion and appears often in KS3–GCSE maths.
- A scale factor multiplies every length by the same amount.
- Use the worked model, help guide, interactive question and flashcards to practise scale factors until the steps feel automatic.
Real-life examples
- Shopping, sport, travel, science, design and everyday decisions all use this skill.
2. Visual
Scale factors 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 Scale factors
- Learn the rule: A scale factor multiplies every length by the same amount.
- Worked model: Identify the scale factor. Multiply lengths by it. For reverse problems, divide by it.
- 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
A shape is enlarged by scale factor 3. A side of 5 cm becomes what length?
6. Flashcards
Master quick recall
Flip each card, then choose whether you know it or need more practice.
0 mastered
FrontRule for Scale factors
BackA scale factor multiplies every length by the same amount.
FrontExample answer: A shape is enlarged by scale factor 3. A side of 5 cm becomes what length?
Back5 × 3 = 15 cm.
FrontCommon check for Scale factors
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.