The concrete for a sidewalk is being poured outside the perimeter of a new subdivision, which is a 280 ft. by 720 ft. rectangle. The building code requires that the sidewalk be 5 feet wide and 8 inches deep. How many cubic yards of concrete will need to be poured?

math:
Dimensions of the rectangle including the sidewalk is
290 by 730 , (added 5 feet on each side)

surface area of sidewalk
= 290x730 - 280x720
=10100 ft^2

volume of sidewalk
= 10100(8/12) ft^3
= 20200/3 ft^3

Final answer: 67333.3(repeating)
I think. I'm not sure.. I really need help. Can someone please help me with the math but explain it with words after it, too? Very confusing..

2 answers

I agree with your method and with your answer
Make sure to divide your answer by 27 to make it in cubic yards