text: It is really the angular error youare looking for.  From your first backsight, which should be a given azimuth, (if not just assume the first backsight is North) add the first angle to that and calculate the next azimuth or bearing, then from there, process each angle to come up with the next azimuth. When you come to the last(closing) angle, compute the last azimuth, which should be the same as your starting azimuth(or 180 degrees  from it). The diffference between your last azimuth and the starting azimuth is your angular error.\n\nI am a PLS in my state, so I guess I am an authority.