The Solution.
The given equation of a circle is

By formula, the equation of a circle is

Comparing the corresponding terms in eqn(1) and eqn(2), we have

Similarly,

Also,
![\begin{gathered} r^2=16 \\ r=\sqrt[]{16}=\pm4 \\ r=\text{ +4 units ( -4 is discarded)} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ongy6gnaeaov3oadl2tv803z8n6w0b7wgd.png)
Hence, the center of the circle is (1,2) while the radius of the circle is 4 units.