Question

2 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:

Part a

Step1: Define scale

Scale is image size to actual size. For width, image width = 1.5 in, actual width = 9 in.

Step2: Calculate scale ratio

Scale = $\frac{\text{Image Width}}{\text{Actual Width}}$ = $\frac{1.5}{9}$ = $\frac{1}{6}$. So scale is 1:6 (image:actual).

Step1: Use the scale

Scale is 1:6, so image height : actual height = 1:6. Image height = 3 in.

Step2: Find actual height

Let actual height be $h$. Then $\frac{3}{h}$ = $\frac{1}{6}$ → $h$ = 3×6 = 18 in.

Answer:

1:6

Part b