Remark
Find the number of cubic feet first, then convert that to cubic yards.
Solution
Formula
V = 4ft * 100 ft * 0.5 feet
V = 200 cubic feet
Conversion Factor
1 cubic yard = 27 cubic feet.
x cubic yards = 200 cubic feet
1/27 = x / 200 Cross Multiply
200*1 = 27*x
200/27 = x
x = 7.41 cubic yards.