the answer is 664 in. here is an example of how to do it
Find the surface area of a rectangular prism with a length of 6 cm, a width of 4 cm, and a height of 2 cm
SA = 2 × l × w + 2 × l × h + 2 × w × h
SA = 2 × 6 × 4 + 2 × 6 × 2 + 2 × 4 × 2
SA = 48 + 24 + 16
SA = 88 cm2