In a pythagorean theorem, how would you reverse the radical form if your trying to find a side of the right trianle

It would be best to keep it the same. So if I knew the hypotenuse was 9 and that one side was 4 and I was looking for the other one I would right it like this:

4^2 + B^2 = 9^2
Then simplify
16 + B^2 =81
Then subtract
B^2 = 65
And then take the square root of both sides
B = 8.0622577483 (since I came up with random numbers it ended up so uneven :P)

Does that make sense to you? I hope that helped you to understand! Feel free to let me know if you have any questions!

- mathwizzard3