You can put this solution on YOUR website! area = 3.41 square km
width is 800 m.
1 km = 1000m
m = 1 km / 1000
800 m = 800 * 1 km / 1000 = .8km
area = 3.41 square km.
width is .8 km.
area = length * width
3.41 square km = length * .8 km.
divide both sides of this equation by .8 km to get:
3.41 square km / .8 km = length
this makes length equal to 4.265 km.
.8 km * 4.265 km = 3.41 square km so the number check out ok.