Is it possible to dissect a circle of radius 9 into 81 equal areas, using only circles? You can dissect a circle of radius $3$ into $9$ equal areas by placing within it $5$ unit circles in an orthogonal cross shape. You could then place $5$ of these radius $3$ circles into a circle of radius $9$ in a similar way. Is it then possible to dissect the $4$ irregular shapes each into $9$ equal areas using only circles? Or is there another entirely different way of achieving a similar result? 

My first thought was to make 80 concentric circles, all centered at the center of the big circle.  Choose radii $r_1, r_2, \cdots, r_{80}$ so that each band of
the dart board has the area $1/81$ of the area of the big circle.
