Question

A model plane is 4 in tall. If it was built with a scale of 4.5 in : 18 ft, then how tall is the real plane?

Answer 1

A model plane is 4 in tall.

It was built with a scale of 4.5 in : 18 ft

$\frac{4.5\: in}{18\: ft}$

To find how tall is the real plane, we can set up the following proportion

$\frac{4.5\: in}{18\: ft}=\frac{4\: in}{x\: ft}$

Where x is the real height of the plane in feet.

$\begin{gathered} \frac{4.5}{18}=\frac{4}{x} \\ x\: \cdot\frac{4.5}{18}=4 \\ x\: =4\cdot\frac{18}{4.5} \\ x=16 \end{gathered}$

Therefore, the real height of the plane is 16 feet.