CalculatingPi

When Run a GUI will appear:

In the top left corner there will be a space to enter an "x" value to evaluate ArcTan(x) on.
In the top right corner there will be a space to enter an "n" value to increase accuracy of all π approximations.
In the bottom left, there is a button labled "solve". This must be pressed in order to evaluate the approximations.

The top four results are π approximations using increasingly accurate combinations of ArcTan values.
The higher the inputted "n" value, the more terms will be included in the taylor polynomial ArcTan approximation, and the more accurate
the estimation of π will be.

The fifth result is simply the ArcTan(x) approximation. This uses the "x value" and "n value". Again the higher the "n value",
the more accurate the approximation will be.

The final result is the great Ramanujan–Sato function. This is the fastest converging function to π known to man.