Question 16753
area of the circle is 64...formula for area is pie * r^2 ,where as formula for circumference or perimeter is 2*pie*r..hence 
 area =pie*r^2=64
r^2=64/pie
 r={{{sqrt(64/pie)}}} =8/{{{sqrt(pie)}}} 
circumference=2*pie*r=2*pie*8/{{{sqrt(pie)}}}= 16*{{{sqrt(pie)}}} ...hence 
16 times the square root of pie  is the answer.