Question

The length of part of a model plane is `0.75` inches and the length of the part on the plane is `2` feet. What is the scale factor?

Answer 1

`SF = 1/32`

Explanation:

The scale factor is the ratio between the image (or model) and the original shape.

Firstly the units must be the same. In this case I will assume that the model is smaller than the original.

`0.75` inch : `2` feet`" "larr` 1 foot = 12 inches

`0.75` inch : `24` inches `" "larr` drop the units

`0.75 : 24" "larr` get rid of the decimal by x 100

`75 : 2400" "larr` change to simplest form `div 25`

`3 : 96" "div 3`

`1 :32`

`SF = 1/32`

This is quite a common scale for model aeroplanes and tanks.
The real life size is 32 times bigger than the model.