Descriptive geometry for students in engineering science and architecture; a carefully graded course of instruction (1915)
Armstrong, Henry F. (Henry Fry), 1868- · New York, J. Wiley & sons, inc.; [etc., etc.] · leaf 78
two inclined lines meet, there is a plane of these lines which has itsH.T. passing through the H.T.s of the two lines; 2. When a line is perpendicular to a plane, the plan of the line and the H.T.of the plane are at right angles to one another; 3. Three lines may meet in a point, and each one be… … Fig. 70. Let there be three lines, .1. B and C, meeting in one pi)int. and containingright angles with each other. If they be equally inclined t > the H.P., the threeright angles will appear in plan equal to one another, and the plans of the rightangles will be 120° in each case, as at (i) in…
Geometry, Descriptive
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