Question 75624
Since we know the circumference, we can find the radius using this formula:

{{{C=2*pi*r}}}
{{{16*pi=2*pi*r}}} Plug in C={{{16*pi}}} to find r
{{{(16*pi)/(2*pi)=cross((2*pi)/(2*pi))*r}}} Divide both sides by {{{2*pi}}}
{{{r=(16*cross(pi))/(2*cross(pi))}}} The pi terms cancel and 16/2=8
{{{r=8}}}
Now use this formula to find the area:

{{{A=pi*r^2}}}
{{{A=pi*8^2}}}
{{{A=64*pi}}} There's the exact answer