We have:
Area of the American flag is:
[tex]A=\text{length}\times width[/tex]Therefore, the length is
[tex]\text{length}=39+52=91[/tex]This is, the length = 91 ft.
For the width, we have 13 stripes on the flag:
[tex]4\times13=52[/tex]The width = 52 ft
Next, the area of the giant American flag:
[tex]A=91\times52=4732[/tex]Answer: 4732 ft^2