Example 4 - Chapter 7 Class 9 Triangles

Last updated at April 16, 2024 by

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Given: AD is bisector of ∠ A So, ∠ BAD = ∠ CAD Also, AD is perpendicular to BC So, ∠ ADB = ∠ ADC = 90° To prove: AB = AC & Δ ABC is isosceles Proof: In ΔABD and ΔACD, ∠ BAD = ∠ CAD AD = AD ∠ ADB = ∠ ADC So, Δ ABD ≅ Δ ACD So, AB = AC Since 2 sides of triangle are equal Δ ABC is an isosceles triangle

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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, Social Science, Physics, Chemistry, Computer Science at Teachoo.