Question

the length of a rectangle is three times its breadth if the perimeter is 84 metre find the length of the rectangle

Answer 1

so let the length and breadth as 3x and x

$perimeter \:would \:be=84$
$2(3x+x)=84$
$8x=84$
$x=84/8$
$x=10.5$

since the length is 3 times of bredth

$3×10.5=31.5$

Answer 2

let the breath of rectangle be ,x
therefore length =3x
perimeter of rectangle=2(l+b)
84=2(3x+x)
84=2×4x
4x=84/2
4x=42
x=42/4
x=10.5
breath =10.5m
therefore length=3×10.5
=31.5m