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If this is correct then in the diagram below AC, the distance from A to C is (6  3)/2 = 1.5 feet. Triangle ABC is a right triangle and hence from the Theorem of Pythagoras AB^{2} = 4^{2}  1.5^{2} = 13.75 and thus AB = √13.75 = 3.7 feet. The shape of the crosssection is a trapezoid and the area of a trapezoid is
In your case this gives
Hence the volume of dirt to be removed is
A cubic yard is 3 feet by 3 feet by 3 feet so its volume is 3 × 3 × 3 = 27 cubic feet and thus the volume of dirt to be removed is
Penny  


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