The length of a rectangle is four times its width.

Area=(length)x(width)=lxb

Now, Since, l=4b

Then, Area=(l)(4l)=4l²=36

Find l and hence, b from above eqn.

4w^2 = 36 so w = 3 cm and L = 12 cm.
Check: 3 x 12 = 36

x = length
y = width

x = 4y (solve by using substitution)
xy = 36

xy = 36
(4y)y = 36
4y^2 = 36
y^2 = 36/4
y^2 = 9
y = √9
y = 3

xy = 36
x(3) = 36
x = 36/3
x = 12

∴ x = 12 , y = 3
(the dimensions of the rectangle are 12 x 3.)

L = 4W

L W = 36
4W² = 36
W² = 9
W = 3 cm
L = 12 cm

A = LW
36 = LW

L = 4W

36 = 4W(W)
36 = 4W^2
9 = W^2
W = 3

36 = L(3)
L = 12

Width: 3 cm
Length: 12 cm

a=4b
P=36 P=a * b
a=? 36=4b*b
b=? 36=4b^2
b^2=9 => b=3
a=4b => a=4*3
a=12

(P=3*12=36 correct)

a- length
b-width

length i believe is three.
width i believe is twelve.