Question

You are preparing a computer presentation to be digitally projected onto the wall of your classroom. Your computer screen is 13.25 inches wide and 10.6 inches high. The projected image on the wall is 53 inches wide and 42.4 inches high. What is the scale factor of the computer screen to the projected image.

Answer 1

The projected image has dimensions 4 times those of the computer screen. The ratio is 1:4.

Explanation:

The ratio of the projected width to the computer screen width is ...

(53 in)/(13.25 in) = 4

The ratio of heights is the same:

(42.4 in)/(10.6 in) = 4

The linear dimensions of the projected image are 4 times those of the computer screen.

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The way the question is written, you may be expected to write this 1 to 4 ratio as the fraction 1 : 4 or 1/4.