# 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?

Jan 26, 2017

$S F = \frac{1}{32}$

#### 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$\text{ } \leftarrow$ 1 foot = 12 inches

$0.75$ inch : $24$ inches $\text{ } \leftarrow$ drop the units

$0.75 : 24 \text{ } \leftarrow$ get rid of the decimal by x 100

$75 : 2400 \text{ } \leftarrow$ change to simplest form $\div 25$

$3 : 96 \text{ } \div 3$

$1 : 32$

$S F = \frac{1}{32}$

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