Question 260112
A rectangular box which is 6 in. by 4 in. by 7 in. is to be wrapped in brown paper. How much paper is required? 

Sol'n:
Let S = surface area required is equal to the material neeeded to wrapped
Surface Area = 2(ab+bc+ca)
             = 2[(6x4)+(4x7)+(7x6)]
             = 2 [24+28+42]
             = 188 sq. in. ----answer