Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 139
Fig. 252. Fig. 253. given line. The projection of a straight line, itself perpendicular to the plane,is the point in which it meets the plane. If the projections a h and a V of a straight line on the two planes L M N 0and L M P Q (Fig. 253) are known, this line A B is determined; for if, throughone…
Mechanical drawing
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