80[tex] \pi [/tex] is the area which equals the pi radius squared. To find the radius you would get radius squared by it's self. So it would just be 80, then you have to square root 80 which equals 4√5 simplified. That is radius squared. So the radius of the small square is 4√5 x 2 which is the diameter then x 2 again to get the larger radius of the big circle. So the answer would be 16√5 pi.
