#include <bits/stdc++.h>
#define int long long
#define double long double
const double pi = 3.14159265358979;
using namespace  std;

void solve()
{
    int n,k;
    cin >> n >> k;
    vector<double>p;
    double one = 1.0;
    for(int i = 0; i < n; ++ i)
    {
        double x,y;
        cin >> x >> y;
        if(y == 0) {
            if(x > 0)
                p.push_back(0);
            else
                p.push_back(pi);
        } else if(x == 0) {
            if(y > 0) {
                p.push_back(pi / 2);
            } else {
                p.push_back(pi * 3 / 2);
            }
        double a = atan(fabs(one * y / x));
        if(x > 0 && y > 0)p.push_back(a);
        if(x > 0 && y < 0)p.push_back(2.*pi-a);
        if(x < 0 && y > 0)p.push_back(pi-a);
        if(x < 0 && y < 0) p.push_back(pi+a);
    }
    sort(p.begin(),p.end());
    double ans = 0.0;
    for(int i = 0; i < n; ++ i)
    {
        if(i + k < n) ans = max(ans, p[i+k] - p[i]);
        else ans = max(ans, p[i+k-n] + 2.*pi-p[i]);
    }
    cout << fixed << setprecision(10) << ans << '\n';
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int _;
    cin >> _;
    while(_--)solve();
}

answer.code: In function ‘void solve()’:
answer.code:44:12: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   44 | signed main()
      |            ^~
answer.code:44:12: note: remove parentheses to default-initialize a variable
   44 | signed main()
      |            ^~
      |            --
answer.code:44:12: note: or replace parentheses with braces to value-initialize a variable
answer.code:45:1: error: a function-definition is not allowed here before ‘{’ token
   45 | {
      | ^
answer.code:51:2: error: expected ‘}’ at end of input
   51 | }
      |  ^
answer.code:8:1: note: to match this ‘{’
    8 | {
      | ^