π to 100 Significant Figures

from decimal import Decimal, getcontext

getcontext().prec = 102  # extra digits for rounding safety

def pi_chudnovsky():
    # Chudnovsky algorithm — converges ~14 digits per term
    C = 426880 * Decimal(10005).sqrt()
    M, X, K, S = Decimal(1), Decimal(1), Decimal(6), Decimal(13591409)
    for k in range(1, 8):
        M = M * (K**3 - 16*K) / (k**3)
        X *= Decimal(-262537412640768000)
        K += 12
        S += M / X * (Decimal(13591409) + Decimal(545140134) * k)
    return C / S

pi = pi_chudnovsky()
print(f"π = {str(pi)[:102]}")  # 1 digit + dot + 100 decimals