top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

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

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

Share this puzzle
Facebook Share Button Twitter Share Button LinkedIn Share Button

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
...