Euclid, [i]The Elements[/i], Book I:[br]Using the procedure in Propositions 2 and 3 to construct the initial diagram for Proposition VIII.[br][br]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![br][br]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.