Search Loci: Convergence:
The mathematical facts worthy of being studied are those which, by their analogy with other facts, are capable of leading us to the knowledge of a physical law. They reveal the kinship between other facts, long known, but wrongly believed to be strangers to one another.
In N. Rose Mathematical Maxims and Minims, Raleigh NC:Rome Press Inc., 1988.
Van Schooten's Ruler Constructions
Solution to Problem VIII
Problem VIII: Above a given straight line AB, to construct an equilateral triangle.
Construction: Cut AB by the second problem, into two equal parts at C, and from C, above AB, by the 5th problem, erect a perpendicular CF and locate on it DC equal to AC or CB. Draw DB and above that construct, as in the 5th problem, a perpendicular to DE at D, and equal to DC, and join EB. I say that if CF is made equal to BE and the triangle AF, FB is made, then the triangle AFB is equilateral.