7. A closed cylindrical can, open at the top (ie. without a top), is to have a closed volume of 900 cm3. Use Calculus to find the minimum surface area of the outside of the can. Give both an exact answer and an approximation rounded to two decimal places. Include correct units on your answer. (Hint: Volume of a cylinder: V = 1724. Surface area of an open-top can: A = ar' + 2arh.)