Answer:
441 yards
Explanation:
it's a square, so all sides are equal. we want to find the area, and the formula for the area of a square is L^2. (Length squared.) The perimeter is found by adding all 4 sides, so dividing the perimeter by 4 gives us the length of each side. 84/4 is 21. the length is 21 yards, so to find the area, we have to square it. 21^2 = 441 yards