Tangent is drawn from a point P to a circle, which meets the circle at T such that PT = 8 cm. A secant PAB intersects the circle in points A and B. If PA= 5 cm, what is the length (in cm) of the chord AB?

8.0 8.4 6.4 7.8

7.8

\( {PT }^{2} \) = PA x PB = \( {PT }^{2} \) = 5 x PB = 64 = 5PB = PB = 12.8cm Then, AB = (12.8 - 5) = 7.8 cm.