The land would be 100x20.
240 is full perimeter.
width is 80m less than length
80+80=160 (because theres 2 width sides)
240-160=80
80/4(because 4 sides)= 20m for each side
20+80=100
20+80=100
20+0=20
20+0=20
add all the sides together and get 240 meters for the full perimeter
