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Question:

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.

Solution:

Let the shorter side be x m
Then diagonal will be x + 60 m
The longer side will be x + 30 m
By Pythagoras theorem,
(x + 60)² = x² + (x + 30)²
⇒ x² + 3600 + 120x = x² + x² + 900 + 60x
⇒ x² + 120x + 3600 = 2x² + 60x + 900
⇒ 2x² - x² + 60x - 120x + 900 - 3600 = 0
⇒ x² - 60x - 2700 = 0
⇒ (x - 90)(x + 30) = 0
⇒ x = 90, -30
Neglecting negative value, we get x = 90
Shorter Side = 90 m
And longer Side x + 30 = 90 + 30 = 120 m
The shorter side is 90 m and the longer side is 120 m.