The perimeter of the flag, which is a rectangle, is equal to twice the length plus twice the width:

Let "w" represent the width of the rectangle. If the length is 410ft greater than the width, you can express the length as follows:

Replace the expression above in the formula of the perimeter:

You know that the perimeter is P= 2,100ft, then:

The next step is to solve for w:
- Distribute the multiplication on the parentheses term:

- Order the like terms together and simplify:

- Subtract 820 to both sides of the equal sign

- Divide both sides by 4

Now that the width is determined, you can calculate the length of the flag:

The width of the flag is 320ft and the length is 730ft