Question

Problem: A scale model of an airplane has a scale of inch = 2 feet the actual length of the plane is 40 feet long. How long is the scale model?

Answer 1

The scale is:

$\frac{1}{4}inch=2\text{ fe}et$

This means that every 1/4 inch in the scale model represents 2 feet of the real plane.

The real length of the plane is:

$40\text{ ft}$

To solve this problem is useful to take the scale:

$\frac{1}{4}inch=2\text{ fe}et$

And find how many inches represent just 1 foot. We can find this by dividing both sides by 2:

$\frac{1}{8}\text{inch}=1\text{feet}$

Now that we know that 1 foot represents 1/8 inches, the last step is to multiply 40 feet by 1/8 and we will find the length of the plane in the scale model:

$40\times\frac{1}{8}\text{inch}=\frac{40}{8}\text{inch}=5\text{inch}$

Answer: the length in the scale model is 5 inches.