Question 4 (c) - Ex 3.1 - Chapter 3 Class 8 Understanding Quadrilaterals

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Ex 3.1, 6 - Chapter 3 Class 8 Understanding Quadrilaterals - Part 4

Ex 3.1, 6 - Chapter 3 Class 8 Understanding Quadrilaterals - Part 5

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Ex 3.1, 6 Find the angle measure x in the following figures (c)Given, ∠A = 30° ∠B = ∠E = x ∠BCX = 70° ∠EDY = 60° XCY is a line, ∠BCX + ∠1 = 180° 70° + ∠1 = 180° ∠1 = 180° − 70° ∠ 1 = 110° XDY is a line, ∠EDY + ∠2 = 180° 60° + ∠2 = 180° ∠2 = 180° − 60° ∠ 2 = 120° In polygon ABCDE, Number of Sides = 5 Sum of the angles = (5 − 2) × 180° = 3 × 180° = 540° Thus, ∠A + ∠B + ∠C + ∠D + ∠E = 540° 30° + x + 110° + 120° + x = 540° 2x + 260° = 540° 2x = 540° − 260° 2x = 280° x = 280/2 = 140° If a polygon has n sides, then the sum of its angles is equal to (n − 2) × 180°

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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.