Editing Unit square (section)

==Rational distance problem==
{{unsolved|mathematics|Is there a point in the plane at a rational distance from all four corners of a unit square?}}
It is not known whether any point in the plane is a [[Rational number|rational]] distance from all four vertices of the unit square.<ref>{{citation
 | last = Guy | first = Richard K. |authorlink = Richard K. Guy
 | title = Unsolved Problems in Number Theory
 | series = Problem Books in Mathematics | volume = 1
 | publisher = Springer-Verlag
 | edition = 2nd
 | year = 1991
 | pages = 181–185
 | doi = 10.1007/978-1-4899-3585-4
| isbn = 978-1-4899-3587-8 }}</ref>