Math CentralQuandaries & Queries


Question from Tracey:

Oh am I confused! I need to know how much fill I would need to cover an area that is 28 feet in diameter by 8 inches deep. Thank you.

Hi Tracey,

I assume you want the volume in cubic yards so you should first convert the dimensions to yards. The diameter of the circle is 28 feet which is 28/3 = 9.33 yards and thus the radius is 9.33/2 = 4.67 yards. The depth is 8 inches which is
8/36 = 0.22 yards. The volume is the area of the circle times the depth and the area of a circle is π r2 where r is the radius. Hence the volume of fill you need is

π x 4.672 x 0.22 cubic yards.


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