Question

find the perimeter of a rectangle whose length is 40cm and diagonal is 41cm

Answer 1

Ans.

Length = 40 cm
Diagonal = 41 cm

So, breadth
$= \sqrt{ {41}^{2} - {40}^{2} } \\ = \sqrt{81} \\ = 9 \: \: cm$

So, the perimeter
=2× (Length + Breadth)
= 2×(40+9) cm
= 98 cm

I HOPE THAT THIS HELPS YOU.

Answer 2

Given

Length =40cm

Diagonal =41cm

(Check figure in image)

Using Pythagoras

Diagonal ²= length ²+ breadth ²

41²=40²+Breadth ²

Breadth ²=41²-40²

breadth²=1681-1600

Breadth²=81

$b = \sqrt{81}$
B=9cm


Perimeter of rectangle = 2(l+b)

=2(40+9)

=2x49

=98cm

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