This question is similar to Chapter 10 Class 10 Circles - Ex 10.2

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https://www.teachoo.com/1832/539/Ex-10.2--6---The-length-of-a-tangent-from-a-point-A-at/category/Ex-10.2/

 

The length of a tangent drawn to a circle of radius 9 cm from a point - CBSE Class 10 Sample Paper for 2026 Boards - Maths Standard

part 2 - Question 18 - CBSE Class 10 Sample Paper for 2026 Boards - Maths Standard - Solutions of Sample Papers for Class 10 Boards - Class 10
part 3 - Question 18 - CBSE Class 10 Sample Paper for 2026 Boards - Maths Standard - Solutions of Sample Papers for Class 10 Boards - Class 10

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Question 18 The length of a tangent drawn to a circle of radius 9 cm from a point at a distance of 41 cm from the centre of the circle is (A) 40 cm (B) 9 cm (C) 41 cm (D) 50 cmSince AB is tangent And, we know that Tangent at any point of circle is perpendicular to the radius through point of contact Hence, OB ⊥ AB ∴ ∠ OBA = 90° So, Δ OAB is a right triangle In right triangle OAB Using Pythagoras theorem (Hypotenuse)2 = (Height)2 + (Base)2 OA2 = OB2 + AB2 412 = 92 + AB2 1681 = 81 + AB2 1681 – 81 = AB2 AB2 = 1681 – 81 AB2 = 1600 AB2 = 16 × 100 AB2 = 42 × 102 AB2 = (4 × 10)2 AB2 = (40)2 AB = √(40^2 ) AB = 40 Hence, Length of Tangent = 40 cm So, correct answer is (a)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 15 years. He provides courses for Maths, Science and Computer Science at Teachoo