To make a scale drawing you shrink every real length by the same scale factor so the whole shape stays in proportion. For a scale 1:n each actual length is divided by n before you draw it.
The method
Convert every actual length to the same unit (usually cm), divide by n, then draw with a ruler. Angles are copied exactly — only lengths change.
Key idea
For a scale 1:n,
Drawing length = Actual length ÷ n
Always convert m → cm (×100) before dividing.
Worked example
Draw a wall of actual length 6 m using a scale of 1:50.
6 m = 600 cm.
Drawing length = 600 ÷ 50 = 12 cm.
So draw a line 12 cm long.
Choosing a scale
Pick a scale that makes the drawing fit neatly on the paper — not too big, not too small. A 20 m field at 1:200 becomes 2000 ÷ 200 = 10 cm, which fits an exercise book easily. If the same field were drawn at 1:50 it would be 40 cm long and run off the page, so a larger n is chosen for larger objects.
Once every side has been divided by n, mark the lengths accurately with a ruler and set-square, then join them at the correct angles. Because all sides shrink by the same factor, the finished drawing is similar to the real object — the same shape, just smaller.
Remember
- Scale 1:n → divide each actual length by n to get the drawing length.
- Change metres to centimetres first (×100).
- Keep every length to the same scale so the shape is not distorted.
- Angles stay the same size in the scale drawing.