The length of the tangent drawn to a circle of radius 12 cm from a point 18 cm away from the centre of the circle is:

$3\sqrt{5}$ cm $6\sqrt{5}$ cm $9\sqrt{5}$ cm $2\sqrt{5}$ cm

$6\sqrt{5}$ cm

In triangle AOB, By using pythagoras theorem, h² = b² + p² OA² = OB² + AB² 18² = 12² + AB² AB² = 324 - 144 AB² = 180 AB = 6√5 cm