Question

A designer builds a model of a bicycle. The finished model is exactly the same shape as the original, but smaller. The scale factor is 2:7. (a) Find the ratio of the height of the model to the height of the original. (b) Find the ratio of the surface area of the model to the surface area of the original. (c) Find the ratio of the volume of the model to the volume of the original. Write these ratios in the format m:n.

Answer 1

Given

Scale Factor of 2:7

When the scale factor is a:b

Recall the following

`\begin{gathered} \text{The ratio of the sides is} \\ a:b \\ \; \\ \text{The ratio of the area is} \\ a^2:b^2 \\ \; \\ \text{The ratio of the volume is} \\ a^3:b^3 \end{gathered}`

Given that the ratio is is 2:7 then we have the following

`\begin{gathered} \text{The ratio of the height of the model to the height of the original is} \\ 2:7 \\ \; \\ \text{The ratio of the surface area of the model to the surface area of the original is} \\ 2^2:7^2\Longrightarrow4:49 \\ \; \\ \text{The ratio of the volume of the model to the volume of the original is} \\ 2^3:7^3\Longrightarrow8:343 \end{gathered}`