In this form, ( h, k) is the center of the circle and r is its radius. Now, let's consider the following diagram.
We can see from the diagram that the center of the circle is ( 8, 6) and its radius is 6.
This information is enough to write the equation.
(x- 8)^2+(y- 6)^2= 6^2
⇕
(x-8)^2+(y-6)^2=36
