the cost of the raw stone is proportional to its weight which is proportional cube of its legnth, i. L*L*L or L^3.

the cost of the raw stone is proportional to its weight which is proportional cube of its legnth, i.e. L*L*L or L^3. Assuming it cost $1000 for one cubic inch of raw stone, we can write the cost of one raw stone as 1000L^3. Let cost of polishing a square inch of the surface area of the rock is $100. Noting that the surface area of rock is proportional to the square of legnth, i.e. L^2 we have cost of polishing the stone as 600L^2(note there are 6 faces to a cube). Assuming there is no cost, what is the expression for the cost of the finished stone and identify the different terms in it.