#include <bits/stdc++.h>
#define ll long long
using namespace std;
const double PI = acos(-1);

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int tt; cin >> tt;
    while(tt--){
        int n, k;
        cin >> n >> k;
        vector<double> a;
        for (int i = 0; i < n; i++) {
            double x, y;
            cin >> x >> y;
            a.push_back(atan2(y, x));
        }
        sort(a.begin(), a.end());
        for (auto d : a) {
            a.push_back(d + 2 * PI);
        }
        double ans = 0;
        for (int i = 0; i < n; i++) {
            ans = max(ans, a[i + k] - a[i]);
        }
        cout << fixed << setprecision(10) << ans << '\n'; 
    }
    return 0;
}