A line is drawn through the point P(4,7) which cuts the circle x² + y² = 9 at the points A and B. Then, PA·PB is equal to?

PA·PB = (PC)² where C is the point of contact of a tangent drawn to the circle from point P. If the center of the circle is O, ΔPOC forms a right-angled triangle where (PO)² = (OC)² + (PC)² ⇒ (4)² + (7)² = 9 + (PC)² ⇒ (PC)² = 16 + 49 = 65. Therefore, PA·PB = 65