#include<bits/stdc++.h>
using namespace std;
typedef  long long LL;
typedef pair<LL,LL> PII;
const int N=2e5+10,M=2e6;
const int mod=998244353;
const LL P=1e9+7;
const LL INF=1e18;
LL h[N],e[M],ne[M],w[M],idx;

LL d[N];
int n;

LL tr[N];

int lowbit(int x)
{
    return x & -x;
}

void add(int x, int c)
{
    for (int i = x; i <= n; i += lowbit(i)) tr[i] += c;
}

LL sum(int x)
{
    LL res = 0;
    for (int i = x; i; i -= lowbit(i)) res += tr[i];
    return res;
}






void solve(){
    double pi=acos(-1);


    int n,k;
    cin>>n>>k;

    vector<double> a(n);

    for(int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;

        if(x==0&&y>0) a[i]=pi/2;
        else if(x==0) a[i]=pi*3/2;
        else a[i]=atan(y/x);

        if(x<0) a[i]+=pi;
        else if(y<0&&x!=0) a[i]+=pi*2;

        //if()

        //cout<<a[i]<<endl;
    }
    
    sort(a.begin(),a.end());

    //for(auto t:a) cout<<t<<endl;
    //cout<<endl;


    double res=0;
    for(int i=0;i<n;i++){
        if(i<n-1&&a[i]==a[i+1]) continue; 

        auto t=a[i];

        int g;
        if(n-i-1<k) g=k-(n-i-1)-1;
        else g=i+k;

        

        if(g<=i) res=max(res,2*pi-t+a[g]);
        else res=max(res,a[g]-t);

        //cout<<g<<" "<<res<<endl;
    }

    printf("%.10lf\n",res);
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int T=1;
    cin>>T;

    while(T--) solve();
 
    return 0;
}