Area of Trapezium

Chapter 9 Class 8 Mensuration
Concept wise

### Transcript

Example 1 (Page 176) The area of a trapezium shaped field is 480 𝑚^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) × h 480 = 1/2 (20 + b) × 15 480 × 2 = (20 + b) × 15 960 = (20 + b) × 15 960 = 300 + 15b 960 – 300 = 15b 660 = 15b 660/15 = b 132/3 = b 44 = b b = 44 ∴ Length of other Parallel side = 44 m Example 2 (Page 177) The area of a rhombus is 240 〖𝑐𝑚〗^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 × d1 × d2 240 = 1/2 × 16 × x 240/8 = x 30 = x x = 30 cm ∴ The length of other diagonal = 30 cm.

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#### Davneet Singh

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.