To find the total amount of fabric needed to cover all three cushions, we need to calculate the surface area of each cushion and then multiply it by 3.
The surface area of a rectangular solid can be found by using the formula: Surface Area = 2(length x width) + 2(width x height) + 2(length x height).
For each cushion, the dimensions are length = 24 in., width = 24 in., and height = 6 in. Plugging in these values into the formula gives us Surface Area = 2(24 x 24) + 2(24 x 6) + 2(24 x 6) = 1152 in².
Since there are three cushions, the total surface area required would be 1152 in² x 3 = 3456 in².
To convert the area from square inches to square feet, we need to divide by 144 (since 1 square foot is equal to 144 square inches). So, the total fabric needed in square feet is 3456 in² / 144 = 24 ft².