supplied
in degrees.
These six items constitute the set of "givens." Note that these data are all relative information
relating the second and third positions to the first. No information about
their absolute locations is needed. The global reference system can be taken to be anywhere
in the plane. We took it to be at the first precision point position PI for convenience.
The free choices ~z and ~3 for the first dyad and "fz, "f3 for the second dyad must
also be input to program FOURBARas they also were to program MATRIX.