Question

a poster is 4 inches by 6 inches and is enlarged to 12 inches by 18 inches. what is the scale factor?
a. 2
b. 3
c. 2.5
d. 4

Explanation:

Step1: Find scale - factor for length

The original length is 4 inches and the new length is 12 inches. The scale factor for length is $\frac{new\ length}{original\ length}=\frac{12}{4}=3$.

Step2: Check scale - factor for width

The original width is 6 inches and the new width is 18 inches. The scale factor for width is $\frac{new\ width}{original\ width}=\frac{18}{6}=3$.
Since the scale factor is the same for both length and width, the overall scale factor is 3.

Answer:

B. 3