I.2 Proposition I.2
To place at a given point (as an extremity) a straight line equal to a given straight line.
Proof
Apply I.1 to obtain an equilateral triangle; produce its sides
(Postulate 2); describe a circle with centre at one endpoint of the
given segment cutting one of the produced sides; the cut-off equals
the given segment by Definition I.15 and Common Notion 1.
lines 74–74 in main.tex