Elements I, Proposition 8 (Setup)
Euclid, The Elements, Book I:
Using the procedure in Propositions 2 and 3 to construct the initial diagram for Proposition VIII.
The proof of Proposition 8 is independent of our ability to construct these two triangles. Their existence is a hypothesis. However, I already have enough tools from the first seven propositions, so I'll build them!
The problem can be set up more simply in Geogebra. I went step-by-step to see how the construction works with a compass and straightedge.