In Fig 5.27, lines l and m are intersected by the transversal t. - Alternate Angles

part 2 - Example 2 - Page 121 - Alternate Angles - Chapter 5 Class 7 - Parallel and Intersecting Lines (Ganita Prakash) - Class 7 (Ganita Prakash & Old NCERT)

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Example 2 - Page 121 In Fig. 5.27, lines l and m are intersected by the transversal t. If ∠a is 120° and ∠f is 70°, are lines l and m parallel to each other? To check parallel, we first find corresponding angles And if corresponding angles are equal, then lines are parallel So, we can find Corresponding angle of a, i.e. ∠ e Corresponding angle of f, i.e. ∠ b Finding ∠ b Now, on line l ∠ a & ∠ b are linear pair ∠ a + ∠ b = 180° 120° + ∠ b = 180° ∠ b = 180° – 120° ∠ b = 60° Now, ∠ b & ∠ f are corresponding angles And they are not equal ∴ Lines l & m are not parallel

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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