The diagonal of a rectangular field is 60 metres more than the shorter side. If the longer side is 30 metres more than the shorter side,
The diagonal of a rectangular field is 60 metres more than the shorter side. If the longer side is 30 metres more than the shorter side, find the sides of the field.
2 Answers
Solution:
Let the length of the shorter side be x metres.
Thus the length of the longer side=(x+30) m
Length of the diagonal=(x+60)m
Each angle of a rectangle=90 degrees
By Pythagoras Theorem, (diagonal)2=(shorter side)2+(longer side)2
(x+60)2 = x2+(x+30)2
x2-60x-2700=0 => (x+30)(x-90)=0 => x=-30 or x=90
As the length of a side cannot be negative,the length of the shorter side = 90 m.
Thus the length of the longer side=120 m
Let the shorter side be ‘a’.
Given, diagonal of a rectangular field is 60 metres more than the shorter side
Diagonal = a + 60
Also, longer side is 30 metres more than the shorter side
Longer side = a + 30
Hypotenuse2 = length2 + breadth2
⇒ (a + 60)2 = (a + 30)2 + a2
⇒ a2 + 120a + 3600 = a2 + 60a + 900 + a2
⇒ a2 – 60a – 2700 = 0
⇒ a2 – 90a + 30a – 2700 = 0
⇒ a(a – 90) + 30(a – 90) = 0
⇒ (a + 30)(a – 90) = 0
⇒ a = 90m
Length of sides = 90m, 120 m