Multiple choice

If AB and AC are two tangents to a circle, ST is another tangent to the circle at the point P on the circle, which intersects AB and AC at S and T respectively. If AB = 15 cm. and TA = 9 cm, then PT is-

  1. 4.5 cm.

  2. 6.5 cm.

  3. 6 cm.

  4. 7.5 cm.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

From external point A, tangents to circle are equal: AB = AC = 15 cm. TA = 9 cm, so TC = AC - AT = 15 - 9 = 6 cm. From external point T, tangents TP and TS are equal: PT = TS = 6 cm.