Step-by-step explanation:
[tex]2\pi {r}^{2} + 2\pi rh[/tex]
[tex]2(3.14) {(20)}^{2} + 2(3.14)(20)(11)[/tex]
[tex]6.28(400) + 6.28(220) \\ 2512 + 1381.6 = 3893.6 {mi}^{2} [/tex]
