**Question:**

Find the centre and radius of each of the following circles :

$(x-3)^{2}+(y-1)^{2}=9$

**Solution:**

The general form of the equation of a circle is:

$(x-h)^{2}+(y-k)^{2}=r^{2}$

Where, (h, k) is the centre of the circle.

r is the radius of the circle.

Comparing the given equation of circle with general form we get:

$h=3, k=1, r^{2}=9$

$\Rightarrow$ centre $=(3,1)$ and radius $=3$ units.

Ans: centre = (3, 1) and radius = 3 units.