The exquation of a circle with center Xc, Yc and raidus r is:
(x - Xc)^2 + (y - Yc)^2 = r^2.
So, find the coordinates Xc, Yc and the radius r.
Xc = (2 + 9) / 2 = = 11/2 = 5.5
Yc = (4 + 4) / 2 = 8/2 = 4
r = (9 - 2) / 2 = 7/2 = 3.5
So the equation is (x - 5.5)^2 + (y - 4)^2 = (3.5)^2 = 12.25
Answer: (x - 5.5)^2 + (y - 4)^2 = 12.25
