geometry
posted by Piggy .
What is the height of a cylinder with a radius of 6 inches and a surface area of 168pi in^2?

Area = 2 pi R^2 + pi R H
Substitute 6 for R.
Area = 72 pi + 6 pi H
= 168 pi
Therefore
96 pi = 6 pi H
and
H = 16 (inches) 
the formula should be
s = 2piRH + 2piR^2
I follow your method and find the
H = 8. Thanks. 
You're right. Senior moment.
Area = 2 pi R^2 + 2 pi R H = 168 pi
72 pi + 12 pi H = 168 pi
12 pi H = 96 pi
H = 8
Good work!