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Find the length and breath of …

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Find the length and breath of a rectangle of perimeter 80cm and area 400sq cm
  • 1 answers

Yogita Ingle 5 years, 6 months ago

perimeter of rectangle  = 80cm

2(l + b) = 80

l + b = 80/2 = 40

l + b= 40 ..... (i)

and area = 400sq cm

lb = 400

l = 400/b ......... (ii)

Put (ii) in (i) , we get

400/b + b = 40

400 + b2 = 40b

b2 - 40b + 400 = 0

(b- 20 ) (b - 20) = 0

b = 20 cm

But b = 20 in (i) we get

l = 20 cm

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