Question

Here is a diagram of a person standing next to a lorry.

The diagram shows two centimetre rulers.
The person and the lorry are drawn to the same scale.
The lorry is approximately 12.8 m in length.
Using the scale diagram, estimate the height of the person in metres.

Answer 1

from the diagram, we can see the Lorry is 12 cm in the model drawing, whilst in actual length is 12.8 metres, now the person on the model drawing shows as 1.5 cm, so

`\begin{array}{ccll} \stackrel{cm}{model}&\stackrel{metre}{actual}\\ \cline{1-2} 12 & 12.8\\ 1.5& x \end{array} \implies \cfrac{12}{1.5}~~=~~\cfrac{12.8}{x} \\\\\\ 12x=(1.5)(12.8)\implies x=\cfrac{(1.5)(12.8)}{12}\implies x=\stackrel{metres}{1.6}`