Answer:
9 ft × 7 ft × 1 ft and 21 ft × 3 ft × 1 ft
Step-by-step explanation:
The formula for the volume of a rectangular prism is
V = lwh
The prime factors of 63 are
3, 3, and 7.
Most raised garden beds are 1 ft deep, so two combinations that would work are
(3 × 3) × 7 × 1 = 9 ft × 7 ft × 1 ft = 63 ft³
3 × (3 × 7) × 1 = 21 ft × 3 ft × 1 ft = 63 ft³