Question 833730
Circumference, {{{c=2*pi*r}}}
{{{C=2*pi*(2r)=2(2*pi*r)}}}
{{{C=2*c}}}


Area, {{{a=pi^r^2}}}
{{{A=pi(2*r)^2=pi*4*r^2=4*pi*r^2}}}
{{{A=4*a}}}