Answer:
1920 square inches
Explanation:
For a rectangular prism, the lateral area can be found by ...
LA = Pl
where P is the perimeter, and l is the length.
For a square pyramid, the lateral area can be found by ...
LA = (1/2)Ph
where P is the perimeter of the base, and h is the slant height of the triangular faces.
For a figure with a square cross section of perimeter P "capped" by square pyramids on either end, the total surface area is the sum of the lateral areas of the three components:
SA = (Pl) + (1/2)Ph + (1/2)Ph
SA = P(l+h) = (4×15 in)(14 +18 in) = (60)(32) in²
SA = 1920 in²
The surface area of the solid seems to be 1920 square inches.
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Caveat
If the figure is something other than what we have tried to describe, your mileage may vary. A diagram would be helpful.