Math CentralQuandaries & Queries


Name: JoAnn
Who are you: Other

Help ! I need to know of many yards of concrete to order for a 14' circle - and 4" thick. Thanks !

Hi JoAnn.

If that 14' is the diameter of your circle, then the radius of the circle is 7'. Since the area of a circle is π r2, the area of your circle is 153.94 square feet. Multiply this by the depth (in feet) of 1/3 feet and you get 51.31 cubic feet of concrete you will need. There are 33 cubic feet in a cubic yard, so divide 51.31 by 33 to get about 1.9 yards of concrete.

Stephen La Rocque.>

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