Source — Euclid's Elements, encoded as an rrxiv paper

X.78 Proposition X.78

If from a straight line there be subtracted a straight line incommensurable in square with the whole which with the whole makes both the sum of squares and twice the rectangle medial and the two sums incommensurable with one another, the remainder is irrational; let it be called that which produces with a medial area a medial whole.

lines 74–74 in main.tex