9. Eric wants to make a cylindrical water tank from sheetmetal. It must have a top and bottom. The tank must be able to contain as much as 12 kL of water. (1 M = lmz) (Hint: Cylinder: volume = nrzh, surface area = 271:7\"2 + 2mh) a. Show that the height of the tank must be given by h = 2 meters tn"2 b. Show that the total surface area of the tank must be given by, A = ZHTZ + 274 meters2 c. Find the dimensions (radius and height) of his tank which uses the least area of sheet-metal