Question

The width of a triangle is 2 thirds of its length if perimeter of rectangle is 135 cm . Find dimensions of a rectangle

Answer 1

so the length be x 
so width = 2/3 x

so perimeter = 2(length + width)
135 = 2(x+2/3x)
5/3x × 2 = 135
x = (135 x 3) / (5 × 2)
x = 40.5 cm

so length = 40.5 cm and width = 2/3 x 40.5 = 27 cm

Answer 2

if it's fully rectangle:

given ,
let length = l
width =2/3l

area of rectangle = 135cm

or

2(l+b) = 135
2( l+2/3l) = 135

$l + \frac{2}{3} l = \frac{135}{2}$

$\frac{3l + 2l}{3} = \frac{135}{2}$

$\frac{5l}{3} = \frac{135}{2}$

$l = \frac{135}{2} \times \frac{3}{5}$

$l = \frac{27}{2} \times 3$

$l = \frac{81}{2}$

l=40.5cm

width=2/3 ×40.5

27 cm

hope it helps you.....