The surface area \( A \) of a cube can be calculated using the formula:
\[ A = 6s^2 \]
where \( s \) is the length of one side of the cube.
For a cube with a side length of 3 ft:
\[ A = 6(3 , \text{ft})^2 = 6(9 , \text{ft}^2) = 54 , \text{ft}^2 \]
So, the surface area of the cube is 54 ft².