BBsecurity_Oficiala

/// 100 P
#include "iostream"
#include "cmath"
#include "iomanip"

using namespace std;

int main(){
    double l, c, h, n;
    cin >> n;
    for(; n-- ;){
        cin >> l >> c >> h;
        if(h == l) /// caz in care cablul este intins la maximum.
            cout << (int)c << ".00\n";
        else if(c / 2 + h == l) /// caz in care cablul atinge pamantul intr-un singur punct.
            cout << "0.00\n";
        else{ /// restul cazurilor, cu ecuatia catenarei intr-un sistem de coordonate
            double a = ((c*c/4)-(l-h)*(l-h)) /(2*(l-h));
            double t1 = 2 * a * log(sqrt(((c*c/4))/(a*a)+1) + ((c/2)/a));
            cout << fixed << setprecision(2) << t1 << '\n';
        }
    }
}