Ah, not quite. The formula for this, I believe, is 2(wl+hl+hw) Meaning your equation would look like: 2(5*12+8*12+8*5) Basically, your final answer is 392 for surface area, I believe.
well first you would do 2(lw+hl+wh). Which is 2(12(5)+12(8)+8(5). If you do the math that would be 2(60+96+40). Then add to get 186. Multiply by 2 to get 372. I hope this wasn't confusing.
