Unsolved Problem 13:

Is there a point in the plane that is at a rational distance from each of the four corners of a unit square?

A rational number is a number that is the ratio of two integers.
A unit square is a square of side length 1.


[Boroczky 1987]
K. Böröczky and G. Fejes Tóth, Intuitive Geometry. North-Holland Publishing Company. New York: 1987. Page 696.
Rational Distances to the Vertices of a Square
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