AI generatedRatio, proportion and rates of changeKey Stage 3

Using a scale drawing

A labelled scale gives a multiplicative link between drawing lengths and real lengths.

  • A labelled scale gives a multiplicative link between drawing lengths and real lengths.
  • Use the length scale separately on each length. State the units of the real measurements.
  • If finding an area, multiply the real lengths; do not apply a length scale only once to an area.

Example 1

A rectangular room is shown on a plan. The scale is 1 cm represents 2 m. Find the real floor area.

Rectangular plan labelled 3 cm by 2 cm; not to scale 3 cm 2 cm Not to scale
Scale the first length.Scale the second length.Multiply the real lengths.

Example 2

A rectangular room is shown on a plan. The scale is 1 cm represents 3 m. Find the real floor area.

Rectangular plan labelled 4 cm by 2 cm; not to scale 4 cm 2 cm Not to scale
Scale the first length.Scale the second length.Multiply the real lengths.

Remember
Use the worked steps to check your method, not just the final answer.

Your turn

Question 1

A rectangular room is shown on a plan. The scale is 1 cm represents 4 m. Find the real floor area.

Rectangular plan labelled 5 cm by 2 cm; not to scale 5 cm 2 cm Not to scale
Check answer
Scale the first length.Scale the second length.Multiply the real lengths.
Question 2

A rectangular room is shown on a plan. The scale is 1 cm represents 2 m. Find the real floor area.

Rectangular plan labelled 6 cm by 2 cm; not to scale 6 cm 2 cm Not to scale
Check answer
Scale the first length.Scale the second length.Multiply the real lengths.
Question 3

A rectangular room is shown on a plan. The scale is 1 cm represents 3 m. Find the real floor area.

Rectangular plan labelled 7 cm by 2 cm; not to scale 7 cm 2 cm Not to scale
Check answer
Scale the first length.Scale the second length.Multiply the real lengths.
Question 4

A rectangular room is shown on a plan. The scale is 1 cm represents 4 m. Find the real floor area.

Rectangular plan labelled 8 cm by 2 cm; not to scale 8 cm 2 cm Not to scale
Check answer
Scale the first length.Scale the second length.Multiply the real lengths.
Question 5

A rectangular room is shown on a plan. The scale is 1 cm represents 2 m. Find the real floor area.

Rectangular plan labelled 9 cm by 2 cm; not to scale 9 cm 2 cm Not to scale
Check answer
Scale the first length.Scale the second length.Multiply the real lengths.
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