#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).unwrap();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().unwrap()
    };
}

fn main() {
    setup! { mut input: SplitWhitespace };

    let t: usize = parse_next!(input);
    let r: Vec<f64> = (0..t).map(|_| parse_next!(input)).collect();

    // h = (3/2) * r
    // l = 2 * (1/sqrt(3)) * h
    // s = l * h * (1/2) = (1/sqrt(3)) * h * h = (9/4) * (1/sqrt(3)) * r * r

    for i in 0..t {
        let ans = (9.0 / 4.0) * (1.0 / f64::sqrt(3.0)) * r[i] * r[i];

        println!("{}", ans);
    }
}