How to write scales as ratios, and use them to find measurements for scale drawings and real lengths with BBC Bitesize Maths. For children between 11 and 14.

A measurement-based scale, eg where 1 cm represents 50 km. A ratio scale in the form 1 : 𝑛, eg the ratio 1 : 30,000 means that every centimetre on the map represents 30,000 cm in real life.