from math import cos, radians, sqrt


def calc_right_triangle_from_length(length: float) -> float:
    return (sqrt(3) * length ** 2) / 4


def main():
    for _ in range(int(input())):
        r = int(input())
        length = 2 * r * cos(radians(30))
        print(calc_right_triangle_from_length(length))


if __name__ == "__main__":
    main()