Van Schooten's Ruler Constructions - Solution to Problem VII

Problem VII:  Given an indefinitely long line AB and a point C away from it, to draw CF which makes an angle with the given line AB which is equal to a given angle E.

Construction:   To the point A in AB, construct, following the previous problem, and angle DAB, equal to E, and draw C, from the 3rd problem, line CF parallel to the line AD:  I say the angle CFB is equal to the angle E.

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Solution to Problem VIII

The other eight problems