Answer:
Width= 85
Length= 485
Step-by-step explanation:
The width will be x, and the length will be x + 400, since it is 400 more than the width.
We know that the perimeter of a rectangle can be found using the equation 2w + 2l.
We plug in the values we have found.
2(x) + 2(x+400) = 1140
4x + 800 = 1140
4x = 340
x = 85
Now we know the width, since it is simply x. To find length all we have to do is add 400.
400 + 85 = 485