You need to find the surface area of the rectangular prism and the triangular prism and add them up to find the answer.
Rectangular prism:
SA=2(lw+wh+lh)
SA=2(437.5+406.25+1137.5)
SA=2(1981.25)
SA=3962.5 sq cm
Triangular prism:
SA=2(1/2bh)+3(slanted height)*w
SA=2(235.75)+3(293.75)
SA=471.5+881.75
SA=1352.75 sq cm
3962.5+1352.75=5315.25 sq cm