Using the perimeter of a rectangle, it is found that she can make a deck of 122 ft wide.
What is the perimeter of a rectangle?
The perimeter of a rectangle of length l and width w is given by:
[tex]P = 2(l + w)[/tex]
In this problem:
- She has enough wood to build a deck that is 280ft, hence P = 280.
- The length is of 10 feet, hence l = 10.
- Considering that the deck's width will be added to the actual width of 8 feet, we have that w = 8 + w.
Then:
[tex]P = 2(l + w)[/tex]
[tex]280 = 2(10 + 8 + w)[/tex]
[tex]36 + 2w = 280[/tex]
[tex]2w = 244[/tex]
[tex]w = \frac{144}{2}[/tex]
[tex]w = 122[/tex]
She can make a deck of 122 ft wide.
You can learn more about the perimeter of a rectangle at https://brainly.com/question/10489198