Question

a photo measures 3 inches by 5 inches and needs to be enlarged to 9 inches by 15 inches. what is the scale factor?
a. 3
b. 5
c. 4
d. 2

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

Explanation:

1. First problem:

Step1: Identify the corresponding side - lengths

The original photo has dimensions 3 inches by 5 inches and the enlarged photo has dimensions 9 inches by 15 inches. We can use either the length or the width to find the scale factor. Let's use the length. The original length is 3 inches and the new length is 9 inches.

Step2: Calculate the scale factor

The scale factor $k$ is found by dividing the new length by the original length. So, $k=\frac{9}{3}=3$.

Step1: Identify the corresponding side - lengths

The original poster has dimensions 4 inches by 6 inches and the enlarged poster has dimensions 12 inches by 18 inches. Let's use the length. The original length is 4 inches and the new length is 12 inches.

Step2: Calculate the scale factor

The scale factor $k$ is found by dividing the new length by the original length. So, $k = \frac{12}{4}=3$.

Answer:

A. 3

2. Second problem: