#/***********************************************************
#    pi2.c -- 円周率
#***********************************************************/
# 相加相乗平均による方法 

a = 1;  b = 1 / Math::sqrt(2.0);  s = 1;  t = 4
for i in 0...3
    last = a;  a = (a + b) / 2;  b = Math::sqrt(last * b)
    s -= t * (a - last) * (a - last);  t *= 2
    printf("%16.14f\n", (a + b) * (a + b) / s)
end

exit 0