What Degrees Are Calculated From
: THE USES OF THE COMPASS AND THE SQUARE
The question that now arises is what line one may use from which to calculate degrees, or at what point in the circle zero is placed. Degrees may be calculated either from the horizontal or from the vertical line. Examine Fig. 53. The working margin indicated by the cross mark is your base line, and in specifying an angle you calculate it from the work edge. Thus, the line A indicates an angle of 30 degrees. The dotted line is 45 degrees.
alt="Fig. 52." title="" height="194" width="335"> Fig. 52.