To solve this problem you must apply the proccedure shown below:
1. The formula for calculate the perimeter of a rectangle is:
[tex]P=2L+2W[/tex]
Where [tex]L[/tex] is the length and [tex]W[/tex] is the width.
2. The length is [tex]100ft[/tex] more than the width, therefore:
[tex]L=W+100[/tex]
3. Substitute values into the formula for calculate the perimeter and solve for the width:
[tex]1260=2(W+100)+2W\\ W=265ft[/tex]
3. Then, the length is:
[tex]L=265ft+100ft\\ L=365ft[/tex]
The answer is: The length is [tex]365ft[/tex] and the width is [tex]265ft[/tex]