@xpil You've probably already tried iterating through lengths and using the Pythagorean theorem to check if the other side is rational.
I haven't gotten far with this other idea, but a little research introduced me to:
(a) Euclid's formula for Pythagorean triples
(b) Heron's formula / Heronian triangles
These are both fairly new ideas to me and I'm not really sure how to apply them to this problem. However, they /might/ make a faster solution?
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