The height of the cylinder is 4 inches. We'll be analyzing the surface area of a round cylinder - in other words the amount of material needed to "make a can". A cylinder (round can) has a circular base and a circular top with vertical sides in between. Let r be the radius of the top of the can and let h be the height. The surface area of the cylinder, A, is A = 2mr2 + 2rrh (it's two circles for the top and bottom plus a rolled up rectangle for the side). = radius Areas = 1 72 h = height Area = h(2ar) Circumference Part a: Assume that the height of your cylinder is 4 inches. Consider A as a function of r, so we can write that as A (r) = 2 mr2 + 8 mr. What is the domain of A (r)? In other words, for which values of r is A (r) defined