Centre (1,2), radius 5

Answer 1

Easy...

(Cx,Cy)

( 1, 2)

so Cx=1 and Cy=2 are the x and y for the Center

The formula for the circle is

(x-Cx)^2 + (y-Cy)^2 = r^2

radius r = 5, so r^2 = 25

(x-1)^2 + (y-2)^2 = 25