Question 52829
a.) {{{V=pir^2h}}}
{{{V/pir^2=pir^2h/pir^2}}}
{{{V/pir^2=h}}}
V=100 so:
{{{h(r)=100/pir^2}}}
b.) if r=2
{{{h(2)=100/(pi(2)^2)}}}
{{{h(2)=100/(pi4)}}}
{{{h(2)=100/(3.14*4)}}}
{{{h(2)=100/12.56}}}
{{{h(2)=7.96}}}
h(2)=8cm
c. Let r=x, I can't change the x axis to r.  Let h=y, I can't change that either.  
You only need to look at the + side of the graph because you can't have a negative radius. 
{{{graph(300,200,-10,10,-10,10,100/(3.14x^2))}}}