Question

the length of a rectangle is three times its width and the length of its diagonal sex root ten cm the perimeter of rectangle is?

Answer 1

let the width be x and length be 3x

diagonal of rectangle  =6root10

(6root10)^2 =x^2 + 9x^2

36*10 = 10x^2

360 = 10x^2

360/10 = x^2

36= x^2

root36 =x

6=x


its width = breath = 6cm and length =3*6 =18cm

then 

perimeter =2(6+18)

perimeter =2*24

perimeter =48cm

i hope this much will help you

Answer 2

Length of a rectangle be x
3x
3x=36
X=6
With 3times=6x3
18
Perimeter of rectangle =2(l+b)
=2*24
=48

I hope answer is correct