Scale and similar shapes (age 11+)
Use scale factors to interpret and create scale diagrams and maps, calculating real-life distances from map measurements and vice versa
What a learner can do afterwards
- Calculate a real-life distance from a map measurement using a given scale (e.g. 1:25,000)
- Draw a scale diagram of a room using a chosen scale factor
- Convert between map distance and actual distance in problems involving different units
The lesson
A map scale tells you what one unit on the paper stands for in real life. It might be written as a rule, like 1 cm = 10 km, or as a ratio, like 1:25,000. Either way, it links a small measurement to a real, much bigger one.
A map has a scale of 1 cm = 10 km. Pop Island and Sunny Bay are 3 cm apart on the map. Multiply the map distance by the scale: 3 x 10 km = 30 km apart in real life.
Some scales are written as a ratio, like 1:25,000. That means 1 cm on the map equals 25,000 cm in real life, which is 250 m. Change both sides to the same unit first, then switch to a friendlier unit like m or km.
A scale tells you what one unit on paper equals in real life: multiply the map distance by the scale, and keep your units matching.
Watch it
Where it sits
Learn first
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Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.