In this section we look at plans drawn to a particular scale.
A scale is used to represent real life measurements on the smaller plan.
In the example below, we see how to work out "real life" measurements from a plan.
On the left is the plan for a room. The scale for this plan is 1 : 200.|
This means that 1 cm on the plan represents 200 cm (or 2 m) in real life.
To work out the dimensions of the room in real life, we need to measure the room on the plan.
The length of the room in real life must be 3 cm × 200 = 600 cm or 6 m
Perimeters and Areas
When working out perimeters and areas, it is best to convert to the "real life" measurements first, and then do the calculations.
In the plan above, we worked out that the "real life" dimensions of the room are 6 m by 4 m.
The perimeter of this room must be 6 m + 4 m + 6 m + 4 m = 20 m.
The area of this room must be 6 m × 4 m = 24 m².
NOTE: You can not measure accurately from the computer screen, so you need to remember that each small square on
the plan is half a centimetre wide.|
1 cm is the same as the length of 2 small squares.
This will apply for all the questions in this section.