Drawing Aids, Continued
Protractors
To measure and lay off angles from the horizontal without triangles, use a
protractor. A protractor maybe circular or semicircular. Circular
protractors are labeled in quadrants from 0 to 90 degrees or double numbered
from 0 to 360 degrees. Semicircular protractors are double numbered from 0
to 180 degrees. Graduations in one-half degree increments allow accurate
angle protraction.
Figure 2-50 shows a circular and semicircular protractor.
Figure 2-50. —Protractors.
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