Question

If the area of a rectangle is 128 square cm and its length is doubled then its breadth find its perimeter

Answer 1

Let the breadth be x cm
Length=2x cm
Area of the rectangle=128 cm square
lb=128
2x×x=128
2x square=128
x square=128/2
x square=64
x=√64
x=8
Breadth=x=8 cm
Length=2x=2(8)=16 cm
Perimeter of the rectangle=2(l+b)
=2(8+16)
=2(24)
=48 cm

Answer 2

Given,
let length of a rectangle be = 2x
and breadth of a rectangle be = x
area of a rectangle is = 128
l×b=128
2x×x=128
2x^2=128
x^2=64
x=8
therefore the length and breadth of a rectangle are 16cm and 8cm respectively
then, perimeter of the rectangle is =2(l+b)
=2(16+8)
=2(24)
=48cm
therefore perimeter of the rectangle is 48cm