Math CentralQuandaries & Queries


Subject: Cubic Feet
Name: sue
Who are you: Other

How do you calculate cubic feet from inches:
8 1/2 X 11 sheet of paper that is 3/4 inches thick?

We have two responses for you.

Hi Stephen La Rocque.

There are 12 inches in a foot, so there are 123 inches3 (cubic inches) in a foot3 (cubic foot). So multiply things out using inches, then divide by 123.

Hope this helps,
Stephen La Rocque.


Hi Sue,

The cubic feet would be referring to volume, which is computed by multiplying together the height and width and thickness of the paper.

One way to do this is to convert all your measurements to feet first, and then multiply these numbers together to get the volume. Remember there are 12 inches in a foot, so to go from inches to feet we have to divide by 12.

width = 8.5 in = 8.5/12 ft, which is approximately 0.708 ft
height = 11in = 11/12 ft, which is approximately 0.917 ft
thickness = 0.75 in = 0.75/12 ft = 0.0625 ft

So volume is approximately: 0.708ft x 0.917ft x 0.0625ft = 0.041ft^3

A hint for how to do the problem another way (by finding the volume in cubic inches first, and then convert to cubic feet) is in this response to a similar question: .


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