Answer:
C) 550 feet squared
Step-by-step explanation:
Imagine how the surface area of the given figure differs from the surface area of a prism 10 ft by 15 ft by 5 ft without the cutout in the top center. The three 5×5 ft squares that would need to be added to make the prism are of exactly the same area as the three 5×5 ft squares that are the sides and bottom of the cutout.
That is, the area is no different from the area of a 10 ft by 15 ft by 5 ft rectangular prism. That area is ...
A = 2(LW +WH +LH) = 2(10·15 +15·5 + 10·5) ft² = 550 ft²
