A manufacturing firm wants to package its product in a cylindrical container 1 ft. high with surface area 12π ft2. What should the radius of the circular top and bottom be? (Hint: The surface area consists of the circular top and bottom and a rectangle that represents the side cut open vertically and unrolled.)
since A = 2πr(r+h) you need
2πr(r+1) = 12π
r(r+1) = 6
sure looks like r = 2