Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 40
the hypothenuse ; slide the triangle up along the edgeof the ruler until the upper edge of the ruler is sufficiently near to the givenpoint C to allow a line to be drawn through it. Draw the line, and it will beparallel to A B. If the triangle be slid farther up along the edge of the ruler, and a… … Fig. 77. edge of the ruler, and a third line be drawn touching A B, the figure con-structed will be a rectangle; and if E D be laid off on A B, equal to C E, thefigure inclosed is a square (Fig. 79). It wili be seen that the triangle and ruler afford a much readier way of A
Mechanical drawing
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