The width of the rectangle is 4 miles.
Explanation:
The formula for area is a = lw (l represents length, and w represents width). Knowing this, we can fill out the information we know:
28 = 7w
Now, we solve the equation. Since we want 1 w instead of 7, we divide both sides by 7. 28/7 = 7w/7, therefore 4 = w.
