# help - solve dimension problem

by Jen
(utah)

A concrete slab will have the following shape and dimensions:

• Shape: rectangular prism

• Length: 12 feet

• Width: 8 feet

• Volume: needs to be greater than 72 ft³

Calculate how thick the concrete slab must be to satisfy these specifications.

### Comments for help - solve dimension problem

 Feb 09, 2011 Calculate Thickness of Concrete Slab by: Staff The question: The volume of a rectangular slab of concrete needs to exceed 72 cu. ft. If the length is 12 feet and the width is 8 feet, how thick does the concrete slab need to be? The answer: Click the link below to see a 3-D drawing of your problem: http://www.solving-math-problems.com/images/calculate-volume-concrete-slab.png The volume of the slab can be calculated as follows: Volume of Concrete Slab = Length x Width x Thickness These are the known values Volume > 72 cubit feet (volume must be greater than 72 cubic feet) Length = 12 feet Width = 8 feet Thickness = unknown Substituting the known values into the equation Volume of Concrete Slab = Length x Width x Thickness Volume of Concrete Slab = Length x Width x Thickness > 72 cubic feet Length x Width x Thickness > 72 cubic feet (12 feet) x (8 feet) x Thickness > 72 cubic feet The last step is to solve for the Thickness. Note that the answer will be in feet. (12 feet) x (8 feet) x Thickness > 72 cubic feet (96 square feet) x Thickness > 72 cubic feet Divide each side of the equation by 96 square feet (96 square feet) x Thickness > 72 cubic feet (96 square feet) x Thickness/(96 square feet) > (72 cubic feet)/(96 square feet) [(96 square feet)/(96 square feet)] x Thickness > (72 cubic feet)/(96 square feet) (1) x Thickness > (72 cubic feet)/(96 square feet) Thickness > (72 cubic feet)/(96 square feet) Thickness > (72/96) x (ft x ft x ft)/(ft x ft) [note: ft x ft x ft = cubic feet, ft x ft = square feet] Thickness > (72/96) x (ft x ft)/(ft x ft) x ft Thickness > (72/96) x (1) x ft Thickness > (72/96) x ft Thickness > 0.75 ft The final answer: the Thickness must be greater than 0.75 feet (or, greater than 9 inches) Thanks for writing. Staff www.solving-math-problems.com

 Apr 19, 2017 math NEW by: Aiyana She used 225cubic feet of concrete to make her new patio.the patio is a rectangular concrete slab and measures 25feet. How thick is the concret slab?

 May 16, 2019 CONCRETE SLABS NEW by: Anonymous LENGTH, 8 FT WIDTHM, 3 FT THICKNESS, 2 INCHES