Eratosthenes calculated the circumference of the Earth without leaving Egypt. Maybe history used Pyramids bases and shadows to make the measurements of time and distance. Indeed, wrap a piece of string, around a circle and the distance is always the value of 2Pi*2r, and this is why the values work. They are not numeric values just pulled from fresh air, they are measurable values that always ''predict'' the correct results. I never personally use to see the true value of maths, but I am starting to see why the importance of the values match Physical process.