The surface area of a box is just each rectangular side's area. (opposite sides are the same so we end up with 2)
[tex]SA = 2wl + 2wh + 2hl[/tex]
[tex]SA = 2*39*13 + 2*39*12.25 + 2*13*12.25[/tex]
[tex]SA = 1014 + 955.5 + 318.5[/tex]
[tex]SA = 2288\ (units^3)[/tex]
SORRY KUCH