Math CentralQuandaries & Queries


Question from Ron:

I am putting up a flag pole, and I am trying to figure out how much concrete I need for the job. I have a round cardboard cement tube which is 18" across and 24" tall. The bottom of the tube will be filled with 3" of gravel and 3" of sand and the rest will be filled with concrete. Could you tell me how many yards of concrete I need.

Hi Ron,

After the sand and gravel are in the tube you are left with a cylinder with diameter 18 inches and height 24 - 3 - 3 = 18 inches. Now you can use our volume calculator to determine how many yards of concrete are required.


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