1194 inches squared of wrapping paper.
Explanation below:
First, find the area of both the bases. The area of one base would be 20.25 X 10.5 = 212.625. Multiply that by 2 to get both bases: 425.25
Next, get the perimeter and times it by the height. The perimeter is 20.25 + 20.25 + 10.5 + 10.5 = 61.5. 61.5 X 12.5 = 768.75.
Add this value to the base areas and you get the total surface area, 425.25 + 768.75 = 1194.
Hope that helps!
:D®