Van Schooten's Ruler Constructions - Solution to Problem V

Problem V:  Given an indefinitely long straight line AB and a point C on it, to draw a line CF which is perpendicular to the given straight line.

Construction:  Draw, as in the previous problem, any perpendicular DE above AB, and then, from C, by the third, problem, draw a line CF parallel to that.  It will be the one sought.

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Solution to Problem VI

The other eight problems