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  1. Chapter 11 Class 8 Mensuration
  2. Serial order wise

Transcript

Example 1 (Page 176) The area of a trapezium shaped field is 480 ๐‘š^2, the distance between two parallel sides is 15 m and one of the parallel side is 20 m. Find the other parallel side. Given, Area of Trapezium = 480 m2 Height = h = 15 m Length of one Parallel side = a = 20 m Let the length of other Parallel side = b cm Now, Area of trapezium = 1/2 (a + b) ร— h 480 = 1/2 (20 + b) ร— 15 480 ร— 2 = (20 + b) ร— 15 960 = (20 + b) ร— 15 960 = 300 + 15b 960 โ€“ 300 = 15b 660 = 15b 660/15 = b 132/3 = b 44 = b b = 44 โˆด Length of other Parallel side = 44 m Example 2 (Page 177) The area of a rhombus is 240 ใ€–๐‘๐‘šใ€—^2 and one of the diagonals is 16 cm. Find the other diagonal. Given, Area of rhombus = 240 cm2 Length of one diagonal = d1 = 16 cm Let length of other diagonal = d2 = x cm. Now, Area of rhombus = 1/2 ร— d1 ร— d2 240 = 1/2 ร— 16 ร— x 240/8 = x 30 = x x = 30 cm โˆด The length of other diagonal = 30 cm.

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.