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

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.