Question 1069401
{{{system(h*pi*r^2=28,s=surfaceArea,s=h*2pi*r+2*pi*r^2)}}}


You are interested in finding the minimum s.
You said, you have r, but want h.  Use your volume equation.  You can find r in terms of h, or you can find h in terms of r.  It is your choice which you choose.  You want s as a function of one variable.


{{{h=28/(pi*r^2)}}}


{{{s=(28/(pi*r^2))2pi*r+2*pi*r^2}}}-----simplify this.