1)

If  one of the diameters of the circle x2+y22x6y+6=0   is a chord to the circle with centre (2,1), then the radius of the bigger circle is 


A) 6

B) 4

C) 2

D) 3

Answer:

Option D

Explanation:

Equation of circle 

x2+y22x6y+6=0  

77202183_k2.PNG

   

Centre (1,3)   ,r= 1+96=2

OA =   (21)2+(13)2OA=1+4=5

   AB= r=2    and R2=r2+OA2

      R2=4+5    R=3