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A rectangle has perimeter equal to 40cm. What is the maximum possible area of this rectangle?

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A rectangle has perimeter equal to 40cm. What is the maximum possible area of this rectangle?
posted Sep 19, 2015 by Deepak Chitragar

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2 Answers

0 votes

100cm2
i.e
40 = 2(l+w)
l+w =20
l=20-w...........(1)
A = lw
= (20-w)w
=20w-w2
dA/dw =20 -2w
but at maximum A, dA/dw = 0
so 20-2w=0

w=10
which means l=20-10=10
so Area = 10*10=100cm2

answer Sep 21, 2015 by Justine Mtafungwa
0 votes

10 * 10 is a square !
not a Rectangle.

answer Jun 22, 2017 by Chandresh Jardosh
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