Question 927124
{{{C=2*pi*R=80}}}
{{{R=40/pi}}}
For a circle,
{{{A[c]=piR^2}}}
{{{A[c]=pi(40/pi)^2}}}
{{{A[c]=1600pi}}}
For a square,
{{{A[s]=s^2}}}
{{{A[s]=(80/4)^2}}}
{{{A[s]=400}}}