Question

The dimensions of a rectangular photograph are a length of nine centimeters and a width of six centimeters. If the photograph is enlarged proportionally so that the length is 15 centimeters, what would the width of the enlarged photograph be?

A. 18 centimeters
B. 9 centimeters
C. 10 centimeters
B. 12 centimeters​

Answer 1

C. 10 centimeters

Explanation:

Proportions

Two variables are proportional if one is calculated as the other by a fixed constant.

Scaling is a common example of proportional measures. Once a scale factor is set, all the measures get affected by the same factor.

To calculate the factor we divide both measures. The other measure is automatically scaled by the same factor.

The dimensions of a rectangular photograph are L=9 cm and W=6 cm. When the photograph is enlarged proportionally, the new length is L'=15 cm.

This gives us the scaling factor of 15/9.

Applying the same factor to the width, we get W'=6*15/9=10 cm

The width of the enlarged photograph is:

C. 10 centimeters