One of the most important and exam oriented question from Chapter name- circles

Topic – Angle properties of circles

Chapter number- 15

In this question a point outside the circle with distance is given, also length of tangent from that point to the circle also given and we have to find the radius of circle.

ICSE Avichal publication

Understanding ICSE Mathematics

Question 2, exercise 15.3

Solution:CT is the radius

CP = 13 cm and tangent PT = 12 cm

Using Pythagoras theorem

HÂ² = PÂ² + BÂ²

(13)Â² = (12)Â² + (r)Â²

169-144 = rÂ²

25 = rÂ²

âˆ´ r= 5cm

I hope this will help