Answer:
57 square feet
Explanation:
Split the boxes into two parts.
One box measuring 11.5 ft long and 3 ft wide. (Box A)
The second box measuring 7.5 ft long and 3 ft wide. (Box B)
Area (figure) = Area of box A + Area of box B
Area of box A
3 × 11.5 = 34.5 ft²
Area of box B
3 × 7.5 = 22.5 ft²
Area of figure = 34.5 + 22.5
Area of figure = 57 ft²