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DEVELOPMENTS BY SECTIONS

these lines. Upon these perpendiculars are set off the lengths of the correspondingly numbered extension lines in the half-profiles. Attention is called to the fact that points 1 and 5 have no altitudes, since they fall on the horizontal plane upon which the entire figure

Figs. 290-294—Frustrum of Scalene Cone

rests. Straight lines connecting the points established upon these perpendiculars are the true lengths from which the pattern is developed.

The pattern is started by drawing a Horizontal line such as line 1-A of Fig. 294. With A as a center and a radius equal to the