Yes you're correct. I know it's a square. I have found all side lengths to be approximately 7.21 units or âˆš52 and the diagonal from AD and CE are âˆš104 or approximately 10.19 units and they are all at right angles to each other. What are some mathematical statements I can use?

The easiest approach is to show that the diagonals are mutually perpendicular and have a common mid-point. This suffices to establish that ACDE is a square and doesn't require use of Pythagoras.