Here is van Schooten's second problem and his first solution to it.

**Problem II:** Given a straight line with endpoints A, B, to bisect it.

Construction: Take any point C at random away from the line AB, and from A through C draw the indefinitely long line ACD, and locate on that line CD equal to the double of AC, and from D through B make a straight line. In that line, put BE equal to BD, and, joining C, E, I say it bisects AB at F.