Answer:
Solids A and B appear to be similar cubes.
The volume of cube A is 8 cubic feet, so each side of cube A has length 2 feet. It follows that cube A has surface area 24 square feet. The volume of cube B is 729 cubic feet, so each side of cube B has length 9 feet. It follows that cube B has surface area (9^2) × 6 = 81 × 6 = 486 square feet.