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
(3)
O1O=33 and OM=3
⇒O1M=26 and PM=5⇒O1P=7