Answer:
The perimeter of a square is 128, the area when perimeter 84 is 441
Explanation:
When the length of a square arm is l,
the area of a square is A = l^2.
So in your case, A = \sqrt{1024} = l^2
So l is simply, l = 32.
The perimeter of a square is, P = 4.l = 32*4 = 128
Again when the perimeter is, P = 84
l = 84/4 = 21
So then the area is, A = 21^2 = 441