First calculate th feet of lace she haven't used.
9 - 3 = 6 ft
now we can convert feet into yard. we can divide the amount into 3 because it says 3ft is 1yrd
6 / 3 = 2 yards
This is a quick sketch of the problem
the answer is about 235.31 ft
you have to use this equation to get the length of the other side, which is roughly 213 ft:
then it's just Pythagorean Theorem to get the end result:
The maximum area for a rectangle will always be when it is in the shape of a square, meaning all sides are the same length. That being said, if the perimeter is 60, we know that the side of the square is 15km. So now we can square the side to get the area so 15km*15km = 225km^2