How to explain scale diagrams in understanding scale to your student
27 October 2026
Understanding scale diagrams is a key skill for 11+ maths. Scale diagrams help your child work out real-life distances using information from a map or drawing.
Here is a clear example to show how to use a scale ratio to find a real length. This method is often tested in 11+ exams and is similar to questions found on maths.com uk and other practice resources.
Worked example
On a map with scale 1: 25,000, a footpath is 8.4 cm long. What is the real length in kilometres?
Step 1: Multiply the map length by the scale number to find the real length in cm.
8.4 × 25,000 = 210,000 cm
Step 2: Change centimetres to metres by dividing by 100. 210,000 ÷ 100 = 2,100 m
Step 3: Change metres to kilometres by dividing by 1,000. 2,100 ÷ 1,000 = 2.1 km
The correct answer is 2.1 kilometres.
| Step | Calculation | Result |
|---|---|---|
| Map length | 8.4 cm | 8.4 cm |
| Multiply by scale | 8.4 × 25,000 | 210,000 cm |
| Convert to metres | 210,000 ÷ 100 | 2,100 m |
| Convert to kilometres | 2,100 ÷ 1,000 | 2.1 km |
Key insight: Your child can now see how to turn a measurement from a map into a real distance using the scale. They will recognise the steps of multiplying by the scale, then converting units, whenever they see a scale diagram question.
They are ready to try similar problems and build confidence with scale diagrams for the 11+.
