26 Jan
2013
26 Jan
'13
8:30 a.m.
This was a problem posed to me by a friend: Let circle C have center O. Let point P satisfy OP = 4. Draw tangent line L to C at point Q. Place point R on L with QR = 12. Let segment PQ cut C at point S between P and Q, so that PS = 4 and QS = 8. What is the radius of C? I give up on this one. An algebraic solution would be nice, a geometric one better.