PAB and PCD are two secants to a circle. If PA = 10 cm, AB = 12 cm and PC = 11 cm, then what is the value (in cm) of PD?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 20
By secant theorm,
PA × PB = PC × PD
⇒ 10 × 22 = 11 × (11 + x)
⇒ 20 = 11 + x
⇒ x = 9
Hence,
PD = PC + CD = 11 + 9 = 20 cm