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Ex 7.4, 6 - Show that of all line segments drawn from a - Side inequality

Ex 7.4, 6 - Chapter 7 Class 9 Triangles - Part 2

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Ex7.4, 6 Show that of all line segments drawn from a given point not on it, the perpendicular line segment is the shortest. Let the given point be P and line be l We draw two line segments PN & PM such that PM ⊥ MN We have to prove: PM > PN In ΔPNM, ∠P + ∠N + ∠M = 180° ∠P + 90° + ∠M = 180° ∠P + ∠M = 180° – 90° ∠P + ∠M = 90° Since angle can’t be 0 or negative Hence, ∠ M < 90° ∠ M < ∠ N PN < PM ∴ Perpendicular line segment is the shortest Hence proved

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.