Question

a scale drawing of a school bus has a scale of $\frac{1}{2}$ inch to 5 feet. if the length of the school bus is $4\frac{1}{2}$ inches on the scale drawing, what is the actual length of the bus?
a $1\frac{4}{5}$ feet
b 22.5 feet
c 9 feet
d 45 feet

Explanation:

Step1: Set up proportion

Let $x$ be the actual length of the bus. The scale is $\frac{1}{2}$ inch to 5 feet, and the length on the scale - drawing is $4\frac{1}{2}=\frac{9}{2}$ inches. The proportion is $\frac{\frac{1}{2}\text{ inch}}{5\text{ feet}}=\frac{\frac{9}{2}\text{ inches}}{x\text{ feet}}$.

Step2: Cross - multiply

Cross - multiplying gives $\frac{1}{2}x = 5\times\frac{9}{2}$.

Step3: Solve for $x$

Multiply both sides of the equation $\frac{1}{2}x=\frac{45}{2}$ by 2 to get $x = 45$ feet.

Answer:

D. 45 feet