Question 250546
formula for surface area     A = 2 pi r^2 + 2 pi r h
with the ends included
A = 2 pi r^2 + 2 pi r h
 = 2 pi r ( r + 20 )=112pi
56=r^2+20r
r^2+20r-56=0
this gets messy so I will assume we are not including the ends (bases)

or with out the ends
A = 2 pi r h=
A = 2 pi r 10=112pi
20r=112
r=112/20=56/10=5.6