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# Lecture - 2 Chapter 10 Circles

00:00:17 Theorem 10.2 The lengths of tangents drawn from an external point to a circle are equal.

00:11:27 NCERT Exercise 10.2 Question 1 From a point Q, the length of the tangent to a circle is 24 cm and the distance of Q from the centre is 25 cm. The radius of the circle is (A) 7 cm (C) 15 cm (B) 12 cm (D) 24.5 cm

00:14:57 NCERT Exercise 10.2 Question 2 In Fig. 10.11, if TP and TQ are the two tangents to a circle with centre O so that ∠ POQ = 110°, then ∠ PTQ is equal to (A) 60° (C) 80° (B) 70° (D) 90°

00:18:17 NCERT Exercise 10.2 Question 3 If tangents PA and PB from a point P to a circle with centre O are inclined to each other at angle of 80°, then ∠ POA is equal to (A) 50° (C) 70° (B) 60° (D) 80°

00:23:45 NCERT Exercise 10.2 Question 4 Prove that the tangents drawn at the ends of a diameter of a circle are parallel.

00:28:17 NCERT Exercise 10.2 Question 5 Prove that the perpendicular at the point of contact to the tangent to a circle passes through the centre.

00:35:17 NCERT Exercise 10.2 Question 6 The length of a tangent from a point A at distance 5 cm from the centre of the circle is 4 cm. Find the radius of the circle.