In ∆ABC, ˂B = 90° and BD ꓕ AC. If AC = 9cm and AD = 3 cm then BD is equal to

(a) 2√2cm   (b) 3√2  cm   (c) 2√3  cm   (d) 3 √3 cm

Ques 23 (MCQ) - In ∆ABC, ˂B=90˚ and BD ꓕ AC. If AC = 9cm and AD = 3 cm - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ]

part 2 - Question 23 - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ] - Solutions of Sample Papers for Class 10 Boards - Class 10
part 3 - Question 23 - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ] - Solutions of Sample Papers for Class 10 Boards - Class 10

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Question 23 In ∆ABC, ˂B = 90° and BD ꓕ AC. If AC = 9cm and AD = 3 cm then BD is equal to (a) 2√2cm (b) 3√2 cm (c) 2√3 cm (d) 3 √3 cm Let ∠ A = x° In Δ ABC ∠ ACB = 90° − x And, in Δ ABD ∠ ABD = 90° − x For Δ ABD and Δ BCD ∠ ABD = ∠ BCD ∠ BAC = ∠ DAB ∴ Δ ABD ~ Δ BCD Since sides in similar triangle are proportional 𝑨𝑫/𝑩𝑫=𝑩𝑫/𝑪𝑫 3/𝐵𝐷=𝐵𝐷/6 3 × 6 = BD2 18 = BD2 BD2 = 18 BD2 = 9 × 2 BD2 = 32 × 2 BD = 3 × √2 BD = 3 √𝟐 cm So, the correct answer is (b)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo