length = l
width = w
l = 8w
w = w
The area is length * width so
8w^2 = 1800
We can solve this by dividing by 8
w^2 = 225
Then square rooting
w = 15
So because l = 8w
l = 8*15 = 120
The perimeter is 2*length + 2*width
Which is 2*120 + 2*15
Which is 240 + 30 = 270m