Determine how many square centimeters of paper are needed to make a label on a cylindrical can 45 cm tall with a circular base having diameter of 20 cm. Leave answer in terms of π.
a. 450π cm2
b. 4,500π cm2
c. 900π cm2
d. 9,000π cm2
c. To determine the area of the label, we will use the formula for the surface area of a cylinder, area = πdh, which excludes the bottom and top. Substituting d = 20 and h = 45, the area of the label is π(20)(45) or 900π cm2. If you select a, you used an incorrect formula for area, area = πrh. If you select b, you used an incorrect formula for area, area = πr2h.