In the figure, ABCDE is a pentagon with BE ∥ CD and BC ∥ DE. BC is perpendicular to CD. AB = 5cm, AE = 5cm, BE = 7cm, BC =  x − y and CD =  x + y. If the perimeter of ABCDE is 27 cm. find the value of x and y, given x, y ≠ 0

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Question 29 (OR 1st question) - CBSE Class 10 Sample Paper for 2020 Boards - Maths Standard - Part 2

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Transcript

Question 29 (OR 1st question) In the figure, ABCDE is a pentagon with BE ∥ CD and BC ∥ DE. BC is perpendicular to CD. AB = 5cm, AE = 5cm, BE = 7cm, BC = x − y and CD = x + y. If the perimeter of ABCDE is 27 cm. find the value of x and y, given x, y ≠ 0 Since BE ∥ CD and BC ∥ DE, and BC is perpendicular to CD That means that BCDE is a rectangle And, in a rectangle Opposite sides are equal BE = CD 7 = x + y x + y = 7 Now, Given Perimeter of Pentagon = 27 cm AB + AE + BC + ED + CD = 27 5 + 5 + (x – y) + (x + y) + (x – y) = 27 10 + 3x – y = 27 3x – y = 27 – 10 3x – y = 17 Now, our equations are x + y = 7 …(1) 3x – y = 17 …(2) Adding (1) and (2) (x + y) + (3x – y) = 7 + 17 4x = 24 x = 24/4 x = 6 Putting x = 6 in (1) x + y = 7 6 + y = 7 y = 7 – 6 y = 1 So, x = 6, y = 1 is the solution

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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.