If in the given figure radius of smaller and larger circles be 4 and 5 cm. Find the length of chord AB.
6 cm
In ΔAOP since AB is tangent OP⊥AB.
OP = 4cm AO = 5cm
AP2 = AO2 – OP2 = 52 – 42 = 32
AP = 3cm
AB = 2.AP = 2 × 3 = 6 cm [since AB is bisected at P]