"Historically [analytic geometry] arose... from the comparison of curvilinear and rectilinear magnitudes. ...the Egyptians and Babylonians, in their geometry of the circle, took the first steps. The former made a remarkably accurate estimate of the ratio of the area of the circle to the area of the square on the diameter, taking the ratio to be (1 - \frac{1}{9})^2, equivalent to taking a value of about 3.16 for \pi. The Babylonians adopted the cruder approximation 3... (although an instance is known in which the value is taken as 3 \frac{1}{8}), but... recognized that the angle inscribed in a semicircle is right, anticipating Thales by well over a thousand years. Moreover, they were familiar... with the ."