Q.

Let origin lies inside the circle x2+y2-x-2y-c=c>0. A PQ chord through origin (where P,Q lies on circle) is such that OP=2, OQ=8 (where O is the origin), then the radius of the circle is

1 5  
2 6  
3 7  
4 8  

Ans.

(3)

O1O=33  and  OM=3

⇒O1M=26  and  PM=5⇒O1P=7