Mechanical drawing : a manual for teachers and students (1902)
Cross, Anson Kent · Boston : Ginn & Co. · leaf 14
one of 90°. By placingthese triangles upon the T-square, lines at any of these angles witha vertical or horizontal line may be drawn. MA TERIALS AND THEIR USES. Lines parallel to any given line, AB, may be drawn by first plac-ing together two triangles (C and D), so that a side of one (C)… … r- ^ 9^: /S\ c . 1 Lines perpendicular to AB may be drawn by placing either tri-angle upon the other, so that its hypotenuse coincides with AB,and then revolving the triangle through an angle of 90°, into theposition illustrated by the dot and dash lines. Lines at 30°, 45°, and 60° with AB, may be…
Mechanical drawing
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