Algorithm 1: π = 4 * (1 - 1/3 + 1/5 - 1/7 ...)

Algorithm 2: π = 4 * (1 - 1/3 + 1/5 - 1/7 ...)

Algorithm 3: π = √ (6 * (1/1^{2} + 1/2^{2} + 1/3^{2} + 1/4^{2}...) )

Algorithm 4: π = √ (8 * (1/1^{2} + 1/3^{2} + 1/5^{2} + 1/7^{2}...) )

Algorithm 5: π = 2 * (2/1 * 2/3 * 4/3 * 4/5 * 6/5 ...) )