asdwsweq

#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
	int n, a, b, c, d;
	cin >> n;
	cout << fixed << setprecision(6);
	for (int i = 0; i < n; i++) {
		cin >> a >> b >> c >> d;
		cout << (double)(a * c) / (b * d) << endl;
	}
}