Scale drawings and maps
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
1 · Read
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 = 5 km. Pop Island and Sunny Bay are 4 cm apart on the map. Multiply the map distance by the scale: 4 x 5 km = 20 km apart in real life.
Drawing a scale diagram works the other way round. You know the real length and you want the paper length, so divide by the scale instead of multiplying. A wall 8 m long at a scale of 1 cm = 2 m is drawn 8 divided by 2, so 4 cm. Use the same scale for every wall, or the drawing comes out the wrong shape.
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. Both sides have to be in the same unit before you compare them. Once you have the real length in cm, change it to a friendlier unit: 25,000 cm is 250 m, and 100,000 cm is 1 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.
2 · Watch
Take it off screen
Where it sits
Learn first
This opens up
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.