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Question
The pathway of a square paddy field has 5 m width and length of its side is 40 m. Find the total area of its pathway. (Note: Use suitable identity)
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Solution
Given side of the square = 40 m
Also width of the pathway = 5 m
∴ Side of the larger square = 40 m + 2(5) m
= 40 m + 10 m
= 50 m
Area of the pathway = area of large square – area of smaller square
= 502 – 402 
Substituting a = 50 and b = 40 in
a2 – b2 = (a + b)(a – b) we have
502 – 402 = (50 + 40)(50 – 40)
Area of pathway = 90 × 10
Area of the pathway = 900 m2
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