Ok, so
The formula of the surface area of a cylinder is given by:
[tex]S=2\pi r^2+2\pi rh[/tex]We want to solve this equation for h. This is:
[tex]\begin{gathered} S-2\pi r^2=2\pi rh \\ \frac{S-2\pi r^2}{2\pi r}=h \\ \frac{S}{2\pi r}-r=h \end{gathered}[/tex]Therefore,
h = (S)/(2πr) - r
