Chords AB and CD of a circle intersect externally at P. If AB = 7 cm, CD = 1 cm and PD = 5 cm, then the length of PB (in cm) is :

3 10 8 5

3

We have a concept, PD  × PC = PB  × PA 5  × 6 = PB  × (PB + 7) 30 = PB  × (PB + 7) By putting the value of PB = 3 we can satisfy the given equation. so, the value of PB = 3 cm