A triangle with three integer sides? Hardly sensational. If, on a whim, you also required the triangle to be right-angled, just to make things more interesting, we could describe every possibility open to you; this is the famous problem of finding Pythagorean triples (see Tangente 212, 2023). But let us leave triangles behind and explore the world of quadrilaterals.
Integer quadrilaterals
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Finding one whose sides all have integer lengths is just as trivial as it is for triangles: take a square of side 1, for example. Now let us require its diagonals to have integer lengths as well. The square of side 1, whose diagonals have length , no longer qualifies.
