#include <bits/stdc++.h>

#define int int64_t
using namespace std;

const long double PI = acos((long double)-1);

void solve () {
	int n,k;
	cin>>n>>k;
	vector<long double> a(n);
	for(int i=0; i<n; ++i) {
		int x,y;
		cin>>x>>y;
		if(x==0) {
			a[i] = y>0?0.0:PI;
		} else if (y==0) {
			a[i] = x>0?PI/2.0:3.0*PI/2.0;
		} else {
			a[i] = atan((long double)y/(long double)x);
			if(x<0 && y<0) {
				a[i]+=PI;
			}
			if(x<0 && y>0) {
				a[i]+=PI;
			}
			if(x>0 && y<0) {
				a[i]+=2.0*PI;
			}
		}
	}
	sort(a.begin(),a.end());
	long double res = 0;
	for(int i=0; i<n; ++i) {
		long double ar = i+k<n?a[i+k]:(a[i+k-n]+2.0*PI);
		res=max(res,ar-a[i]);
	}
	cout<<setprecision(17)<<res<<'\n';
}

signed main() {
	cin.tie(0);
	ios_base::sync_with_stdio(0);
	int t;
	cin>>t;
	while(t--)solve();
	return 0;
}