math
posted by vincent on .
Number of cubic inches in volume of cube, Number of square inches in surface area of cube. which one is greater or equal?

Side length =L, Vol=L^3, SA=6L^2
If L^3=6L^2 then L=6, that is for 6 inch cube, cubic in will be equal to sq inches. If side is L+a, then say
(L+a)^3>6(L+a)^2 or L+a>6 or L>6a. At a=0 it confirms the first result L=6; for all positive values of a, vol will be>SA, that is cubic inches will be more than sq in.