Two chords AB and CD of a circle are produced to intersect each other at a point P outside the circle. If AB = 7 cm, BP = 4.2 cm and PD = 2.8 cm, then the length of CD is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 14 cm.
Let the length of CD be x cm.
According to the given question,
PA × PB = PC × PD
⇒ 11.2 × 4.2 = (x + 2.8) × 2.8
⇒ x + 2.8 = 16.8
⇒ x = 16.8 - 2.8
⇒ x = 14 cm