Area of a rectangle= length*width
Here you are given the width but not the length. But also you are given the perimeter.
Perimeter of a rectangle= 2(length+width)=18
so, [tex]length+width= \frac{18}{2} =9[/tex]
width=7, so [tex]length+7=9[/tex]
so, [tex]length=2[/tex]
Now, you have the length=2 miles and width=7 miles
You can simply get you area.
[tex]Area= length*width=2*7=14miles^2[/tex]
The answer is 14 sq miles.
Hope this helps.
