100,000 equals 10 to the power of 5, hope helps.
For any circle with Cartesian equation

,
we have that the centre of the circle is

, and the radius of the circle is

.
So in the case that

,
we essentially have that

.
So the centre of the circle is

, and the radius is

.
It could 20 divided by 4 and add 6.
i hope this helps.