1 yard contains 3 feet. Then to find how many cubic feet are in 1 cubic yard you raise both to the power 3. this is: 1 yard = 3 feet => (1 yard)^3 = (3 feet)3 => 1 yard^3 = 27 feet^3. Now you have to multiply by 3 to get the number of cubic feet in three cubic yards => 3 * (1 yard^3) = 3 (27 feet^3) => 3 yard^3 = 81 feet^3, then there are 81 cubic feet in 3 cubic yards.