A scale is a ratio you can walk
A map is marked 1 : 50,000. Two villages are 4 cm apart on it. How far apart are they?
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Step 1 of 4
- 4 cm on the map.
- × 50,000 → 200,000 cm on the ground.
- ÷ 100 → 2,000 m.
- ÷ 1000 → 2 km.
The rule
The villages are 2 km apart on the ground.
A scale compares a length on paper with the real length. Take a scale of 1 : 50,000. Both numbers use the same unit. So the scale has no unit. Here 1 cm on paper stands for 50,000 cm on the ground. On a 1 : n scale, real length is paper length times n.
A plan is a drawing of a house or room. On a 1 : 200 plan, 6 cm stands for 6 × 200 cm. That is 1,200 cm. And 1,200 ÷ 100 = 12 m.
To change units: 100 cm make 1 m. 1,000 m make 1 km.