Question 866674
Since the circle goes through points
(7,6),(11,6)
the diameter =4 and radius =2
and the center is at (9,6)
(9,4) is also on the circle

(x-9)^2+(y-6)^2=4

These equations are valid and yield the same results as above
(7-h)^2+(6-k)^2=r^2, 
(11-h)^2+(6-k)^2=r^2 ,
(9-h)^2+(4-k)^2=r^2

h = 9,   k = 6,   r = 2
(x-9)^2+(y-6)^2=4