Scale drawings and maps · Year 7
In Year 7 you learn: scale drawings and maps.
Maps, plans and models are drawn to scale: every length is the real length divided by the same number. A scale written as a ratio like 1 : 50,000 means 1 cm on the drawing is 50,000 cm in real life, using the same unit on both sides.
Key facts
- Real length = drawing length × scale number.
- Drawing length = real length ÷ scale number.
- In a ratio scale 1 : n both parts are in the same unit.
- Useful: 100 cm = 1 m and 100,000 cm = 1 km.
- Areas on a plan scale by the scale number squared, so convert lengths first, then work out the area.
Worked examples
Example 1
On a map, 3 cm represents 1.5 km. Write the scale in the form 1 : n.
Answer: 1 : 50,000