#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<unordered_map>
#include<random>
#include<array>
#include<cassert>
#include<list>
#include<fstream>
using namespace std;
#define INF ((1<<30)-1)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()



int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int n;
	cin >> n;
	rep(_, n) {
		double a, b, c;
		cin >> a >> b >> c;

		double s = sqrt(a * a + 4 * c / 20 / b);
		double v = (-a + s) / 2 * 20 * b;

		printf("%.2f\n", max(0.0, (v / 1000 * 3600) - 0.000));
	}

	return 0;
}