Figure 1
\((x-1)^{2}+(y-2)^{2}=C,\) \(C>0\)
\((x-1)^{2}+(y-2)^{2}=C,\) \(C>0\)\((x-1)^{2}+(y-2)^{2}=C,\) \(C>0\) \((x-1)^{2}+(y-2)^{2}=C,\) \(C>0\)