A rectangular field is to be enclosed with 1120 feet of fencing. If the length of the field is 40 fe

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A rectangular field is to be enclosed with 1120 feet of fencing. If the length of the field is 40 feet longer than the width, then how wide is the field?

We're given:

1. l = w + 40

And we know the perimeter of a rectangle is:
P = 2l + 2w

Substitute (1) into this formula as well as the given perimeter of 1120:
2(w + 40) + 2w = 1120

Multiply through and simplify:
2w + 80 + 2w = 1120

Group like terms:
4w + 80 = 1120

Typing this equation into our search engine, we get:
w = 260