Question

$\text{A small airplane has a wingspan of 15 ft. The}$ $\text{scale factor for its model is}\frac{1}{60}\text{. Find the}$
$\text{wingspan of the model in inches.}$

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

The correct option is B 3

Given:
$\bullet \text{Actual wingspan = 15 ft}$
$\bullet \text{Scale factor =}\frac{1}{60}$

Let, the wing span of the model = x ft

We know that,

Scale factor
= $\frac{\text{Dimension of scale model}}{\text{Dimension of actual object}}$

$\Rightarrow \frac{1}{60}=\frac{x}{15}$

Multiplying both sides by 60,

$\Rightarrow \frac{1}{60}\times 60=\frac{x}{15}\times 60$

$\Rightarrow 1=x\times 4$

Dividing both sides by $4$,

$\Rightarrow \frac{1}{4}=\frac{x\times 4}{4}$

$\Rightarrow \frac{1}{4}=x$

$\therefore$ $\text{Wingspan of the model =}\frac{1}{4}\text{foot}$

But we need to find the wingspan of the model in inches.

$\because$ 1 foot = 12 inches

$\therefore$ $\frac{1}{4}\text{foot =}\frac{1}{4}\times \text{12 = 3 inches}$

Hence, the wingspan of the model is 3 inches.