A new sidewalk will be 4 feet​ wide, 300 feet​ long, and filled to a depth of 3 inches ​(0.25 ​foot) with concrete. How many cubic yards of concrete are​ needed?

Answer 1

4 by 300 by 1/4 feet

= 4/3 by 100 by 1/12 yards

= (4/3)(100)(1/12)

= 100/9

= 11 1/9 cubic yards

or

4(300)(1/4) = 300 ft^3

= 300/3^3 = 300/27 = 11 1/9 = 11.111... cubic yards

1 cubic yard = 3^3 = 27 cubic feet