Answer:
332 ft²
Step-by-step explanation:
The total area of the fish tank is the sum of the areas of the base and the walls.
The area of a rectangle is A = side 1 × side 2
Base
A = 12 ft × 5 ft = 60 ft²
2 8×12-walls
A = 8 ft × 12 ft = 96 ft²
2 walls: 2 × 96 ft² = 192 ft²
2 5×8-walls
A = 5 ft × 8 ft = 40 ft²
2 walls: 2 × 40 ft² = 80 ft²
Total area: 60 ft² + 192 ft² + 80 ft² = 332 ft²
