In the adjoining figure the diameter of the larger circle is 10 cm and the smaller circle touches internally the larger circle at P and passes through O, the center of the larger circle. Chord SP cuts the smaller circle at R and OR is equal to 4 cm. What is the length of the chord SP?
6 cm
OP is the diameter of the smaller circle
∠ ORP = 90 (Angle subtended by a diameter)
In triangle ORP
RP2 = OP2 – OR2
RP2 = 52 – 42
RP = 3
Similarly, SR = 3
SP = 3 + 3 = 6 cm