Modern metal cans, like the one shown, are usually made of steel, and then covered with a thin layer of tin. 

A. Write an inequality representing the amount of sheet metal that can be used to make a can that is 10cm tall. 

B. Graph the inequality.

C. Explain how the graph can be used to determine the minimum amount of metal required for cans of various radii.

d. explain a factor that the surface area of a cylinder does not account for. 

e. suggest a change to a surface area of a cylinder inequality that would make it more accurately represent the amount of metal required to make a tin can like the one shown.