Chord AB and diameter CD of a circle meet at the point P, outside the circle when produced. If PB = 8 cm, AB = 12 cm and the distance of P from the centre of the circle is 18 cm, the radius (in cm) of the circle is closest to:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 12.8.
Let the radius of the circle = r
⇒ 8 × 20 = (18 - r) × (18 + r)
⇒ 160 = 324 - r2
⇒ r2 = 164
⇒ r = 12. 8062
The radius of the circle is 12.8cm