#include<bits/stdc++.h>
using namespace std;

using ll = long long;
double pi = acos(-1.0);
double eps = 1e-9;

bool check(pair<int, int> a, pair<int, int> b){
    vector<bool> ispos(4);
    if(a.first >= 0)ispos[0] = true;
    if(a.second >= 0)ispos[1] = true;
    if(b.first >= 0)ispos[2] = true;
    if(b.second >= 0)ispos[3] = true;

    return (ispos[0] == ispos[2] && ispos[1] == ispos[3]);   
}
void solve() {
    int n, k;
    cin >> n >> k;

    vector<pair<pair<ll, ll>, int>> pos, neg; 
    vector<ll> x(n), y(n);
    

    for(int i = 0; i < n; i++){
        cin >> x[i] >> y[i];
        if(y[i] >= 0)pos.push_back({{x[i], y[i]}, i});
        else neg.push_back({{x[i], y[i]}, i});
    }

    sort(pos.begin(), pos.end(), [&](const pair<pair<ll, ll>, int> &xx, const pair<pair<ll, ll>, int> &yy){
       return (xx.first.first * yy.first.second > xx.first.second * yy.first.first); 
    });
    sort(neg.begin(), neg.end(), [&](const pair<pair<ll, ll>, int> &xx, const pair<pair<ll, ll>, int> &yy){
       return (xx.first.first * yy.first.second > xx.first.second * yy.first.first); 
    });

    for(auto t : neg){
        pos.push_back(t);
    }
    
    if(pos.front().first.first * pos.back().first.second == pos.front().first.second * pos.back().first.first && check(pos.front().first, pos.back().first)){
        cout << fixed << setprecision(10) << pi * 2 << '\n';

        return;
    }
    double mx = 0.0;

    for(int i = 0; i < n; i++) {
        int j = (i + k) % n;

        double w1 = atan2(pos[j].first.second, pos[j].first.first) - atan2(pos[i].first.second, pos[i].first.first);
        
        if(w1 < 0.0){
            w1 += 2 * pi;
        }
        
        mx = max(mx, w1);
    }
    cout << fixed << setprecision(10) << mx << '\n';
}

int main() {
    ios::sync_with_stdio(0); cin.tie(nullptr);
    int t = 1;
    cin >> t;
    while(t--) {
        solve();
    }
}