Question

an image of a book shown on a website is 1.5 inches wide and 3 inches tall on a computer monitor. the actual book is 9 inches wide. a. what scale is being used for the image? b. how tall is the actual book?

Explanation:

Step1: Find the scale factor

The image width is 1.5 inches and the actual width is 9 inches. The scale factor $k$ for width is found by dividing the image - width by the actual width, $k=\frac{1.5}{9}=\frac{1}{6}$.

Step2: Calculate the actual height

The image height is 3 inches. Let the actual height be $h$. Since the scale factor is the same for both width and height, we use the proportion $\frac{\text{image height}}{\text{actual height}}=k$. So, $\text{actual height}=\frac{\text{image height}}{k}$. Substituting the values, $h = 3\div\frac{1}{6}=3\times6 = 18$ inches.

Answer:

18 inches