#include <bits/stdc++.h>
using namespace std;
#define max_len 200010
double arr[max_len];
int N;
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
double get_cha(double beg, double end)
{
    if(beg <= end)
    {
        return end - beg;
    }
    else
    {
        return 2 * M_PI + end - beg;
    }
}
void sol()
{
    int k;
    cin >> N >> k;
    for (int i = 0; i < N; i++)
    {
        int a, b;
        cin >> a >> b;
        arr[i] = atan2(b, a);
    }
    sort(arr, arr + N);
    if(N == k)
    {
        printf("%.8lf\n", M_PI * 2);
        return;
    }
    double ans = 0;
    for (int i = 0; i < N; i++)
    {
        ans = max(ans, get_cha(arr[i], arr[(i + k) % N]));
    }
    //cout << ans << "\n";
    printf("%.8lf\n", ans);
    
}
int main()
{
    int T;
    cin >> T;
    while (T--)
    {
        sol();
    }
    
}