Scale diagrams often have both a scale and a grid. For example, a diagram has a scale of 1:50, and the grid is shown at 1cm intervals on the diagram: 1cm represents 50cm in real life, or 0.5m.
1. The plan of the ground floor of a house is shown below. How long is the sitting room?
Measure along a grid line for 6.3 grid places.
2. The overall dimensions of the house are 8m by 6m. The plan is 16cm by 12cm. What is the scale of the plan?
Using the length,16cm represents 8m, or 16 : 800 (make both units centimetres).
Dividing both sides by 16 gives 1 : 50.
Check with the width: 12 : 600 simplifies to 1 : 50.