Hello, wale!
Did you make any sketches?
Find the equations of the two horizontal tangents to the circle. Code:

 (3,8)
   + * o *   
*  : *
*  : *
*  : r=6 *
 :
*  : *
*  o(3,2) *
*  : *
 :
*+:*
*  : *
*  : *
   + * o *   
 (3,4)

Got it?
Find the coordinates of the endpoints of the diameter whose equation is Code:

 * * *
*  * *
*  o
*  * *
 *
*  * *
*  o (2,2) *
*  * *
    +          
* *  *
o  *
* *  *
 * * *

We want the intersections of: .
Substitute [2] into [1]: .
. . . . . . .
Hence: .
Therefore, the endpoints of the diameter are: .