Answer: 380 ft and 780 ft
Explanation:
We can assume that the flag is a rectangle. If the width of the flag is w, then the length is w + 400.
The formula for the perimeter of a rectangle is
. Let's plug in the values we know.
We know that the length is 400 more than the width, so let's find the length.
Hence, the flag's width is 380 ft and the length is 780 ft.