Chord AB of a circle when extended meets the tangent to the circle at point P. PT is the tangent touching the circle at point T. If lengths of PT and PB are 6 cm. and 4 cm. respectively, what is the length of PA?

Answer : Option A

Explanation :

PB. PA = PT2

⇒ 4 × PA = 6 × 6

$Rightarrow mathrm{PA}=frac{6 imes 6}{4}=9 mathrm{~cm}$