Question 772065
r for radius
h for height
total surface area A.
{{{A=2*pi*r^2+2*h*pi*r or A=2*pi(r^2+hr)}}}


As given, {{{A=100=2*pi(r^2+hr)}}}
{{{pi(r^2+hr)=50}}}
{{{r^2+hr=50/pi}}}
{{{hr=50/pi-r^2}}}
{{{h=(50/pi-r^2)/r}}}
{{{highlight(h=50/(pi*r)-r)}}}