#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef long double ld;
using namespace std;
const int N=200010,M=2000010,INF=0x3f3f3f3f;
const ld eps=1e-11,pi=acos(-1);
int T,n,k;
struct node{
	ll x,y;
	node(ll xx=0,ll yy=0){x=xx,y=yy;}
	void in(){cin>>x>>y;}
	void out(){cout<<'('<<x<<','<<y<<')'<<'\n';}
	bool operator <(const node &a)const{
		return x!=a.x?x<a.x:y<a.y;
	}
	bool operator ==(const node &a)const{
		return x==a.x&&y==a.y;
	}
};

node operator +(const node &a,const node &b){return node(a.x+b.x,a.y+b.y);}
node operator -(const node &a,const node &b){return node(a.x-b.x,a.y-b.y);}
ll operator *(const node &a,const node &b){return a.x*b.x+a.y*b.y;}
ll operator ^(const node &a,const node &b){return a.x*b.y-a.y*b.x;}

ld len(node a){return sqrt((ld)(a*a));}

node O(0,0),P(-1,0);
bool cmp2(node a,node b){
	//Polar sorting
	if(((a-O)^(b-O))==0){
		if(a*b>0)return a*a<b*b;
		else if((a^P)==0)return a.x<b.x;
		else return (a^P)<(b^P);
	}
    if(((P-O)^(a-O))==0&&(P.x-O.x)*(a.x-O.x)>0)return 1;
    if(((P-O)^(b-O))==0&&(P.x-O.x)*(b.x-O.x)>0)return 0;
    if((((P-O)^(a-O))>0)!=(((P-O)^(b-O))>0))return ((P-O)^(a-O))>((P-O)^(b-O));
    return ((a-O)^(b-O))>0;
}

node p[N<<1];

ld ans;

void solve(){
	ans=0;
	cin>>n>>k;
	for(int i=1;i<=n;i++)
		p[i].in();
	if(n==k){
		cout<<fixed<<setprecision(15)<<2.0*pi<<'\n';
		return;
	}
	sort(p+1,p+n+1,cmp2);
	for(int i=1;i<=n;i++)p[i+n]=p[i];
	for(int i=1,j=1;i<=n;i++){
		while(j-i+1<=k)j++;
		ld cs=(p[i]*p[j])/(len(p[i])*len(p[j]));
		ld theta=acos(cs);
		if(fabs(cs-1)<eps)theta=0;
		if((p[i]^p[j])<0)theta=2.0*pi-theta;
		if(!(p[i]^p[j])&&(p[i]*p[j])<0){
			theta=pi;
		}
		if(!(p[i]^p[j])&&(p[i]*p[j])>0){
			if(k==1)theta=0;
			else theta=2.0*pi;
		}
		ans=max(ans,theta);
	}
	cout<<fixed<<setprecision(15)<<ans<<'\n';
}
int main(){
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	cin>>T;
	while(T--)solve();
	return 0;
}
/*
 5
 1 1
 0 1
 8 2
 1 0
 1 1
 0 1
 -1 1
 -1 0
 -1 -1
 0 -1
 1 -1
 4 2
 -1 1
 0 1
 0 2
 1 1
 4 2
 -1000000000 0
 -998244353 1
 998244353 1
 1000000000 0
 3 1
 0 1
 0 2
 0 -1
 
 1
 4 2
 -1000000000 0
 -998244353 1
 998244353 1
 1000000000 0
*/