Question 23870
The standard form of the equation of a circle whose centre is at (h, k) and whose radius is r is:
{{{(x-h)^2 + (y-k)^2 = r^2}}} compare this with your equation:
{{{(x-1)^2 + (y-2)^2 = 2^2}}}

From this point, you can read off the coordinates of the centre and the length of the radius.
The centre is at (1, 2) and the radius is 2.