From the point inside a square, the distance to three corners is 4, 5, and 6 cm, respectively.
Find the length of the side of a square.
I have not worked it out properly. I just drew the pic.
Looks like about 7
https://www.geogebra.org/classic/grbxekvu
Maybe you can get some ideas from what I have done so far.
(the diagram is interactive)
Correction...
The length of the side of a square is 7.534 cm.