O is the centre of the circle, and AB is a chord. P is a point on AB. PA=3 centimeters, PB-8 centimeters, OP= 5 centimeters what is the radius of the circle?
In the figure, BC is a chord and PA is a tangent to the circle. PB=4 centimetres, PA=6 centimetres, the length of the chord BC is: