Elements of descriptive geometry, with applications to isometric projection and othe forms of one-plane projection; a text-book for colleges and ingineering schools by O. E. Randall.

THE POINT, LINE, AND) PLANE

15

Fig. 14 shows how the projections of Fig. 13 will appear after
H and V take their position of coincidence.
In Fig. 15, M-N represents a straight line located by the point
M in the third quadrant and by the point N in the first quadrant.
The line pierces V at a' and pierces H at b,. The section M-b, of
the line is in the third quadrant, the section b,-a' is in the second
quadrant, and the.section a'-N is in the first quadrant.

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V FIG. 17 FIG. 18
Fig. 16 shows how the projections of Fig. 15 will appear after
H and V take their position of coincidence.
In Fig. 17, M-N represents a straight line located by the point
M in the fourth quadrant and by the point N in the second quadrant. The line pierces H at b,, runs through the first quadrant,
and pierces V at a'.
Fig. 18 shows how the projections of Fig. 17 will appear after
H and V take their position of coincidence.