SOLUTION: When the dimensions of a cube are reduced by 4 inches on each side, the surface area of the new cube is 864 square inches. What were the dimensions of the original cube?
Step 1: The area of each face of the smaller cube is = 144 square inches.
Step 2: The edge length of the smaller cube is = 12 inches.
Step 3. The edge length of the original cube is 12+4 = 16 inches.
Answer. The edge length of the original cube is 16 inches.