Back in the day before PCs and when GPS was under tight military/FAA control:
Square or rectangle plots: Area = length x width in feet...a step or pace = 3'
Circle plot: Area = 3.1416 X (radius x radius) in feet....where radius = half of the steps of plot diameter
Then going back even further with only land lines and snail mail and some monstrous interest rates of the 70s and 'tight $$' and 'Nixon' and Nam:
an acre square was semi-formally ~210' x 210' or informally 70 paces by 70 paces.....you either borrowed a long tape and measured (corner to corner also for square) or 'stepped it off' and shook hands!
Then going back much further to government land survey.....chains were used to mark section lines.http://en.wikipedia.org/wiki/Chain_(unit
What is interesting is that our section corners marked by GPS survey are roughly 15' NE of the 'stones' marking the older chained land survey. That can get touchy when time for new fencing 'on the line'...which line new or old?
Marking of the earth is quite comical IMO!