approximate_pi
def approximate_pi(n, d=2):
r = d/2
a = 360/n
x = (2 * r**2 * (1 - math.cos(math.radians(a))))**0.5
perimeter = x * n
pi = perimeter / d
return pi
for n in [3,4,5,10,100,1000,10000,100000]:
print(n, "-->", approximate_pi(n))