The formula for this is [tex]A=2 \pi rh+2 \pi r^{2} [/tex]. If the diameter is 8 the radius is 4, so filling in accordingly we have [tex]A=2 \pi (4)(12)+2 \pi (16)[/tex] and [tex]A=96 \pi +32 \pi [/tex] which is [tex]A=128 \pi [/tex] and when you multiply in 3.14 you get that A = 401.92 or B above.
