//#define _GLIBCXX_DEBUG

//#pragma GCC target("avx2")
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")

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


#ifdef LOCAL
#include <debug_print.hpp>
#define OUT(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define OUT(...) (static_cast<void>(0))
#endif

#define endl '\n'
#define lfs cout<<fixed<<setprecision(15)
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()
#define UNIQUE(a) (a).erase(unique((a).begin(),(a).end()),(a).end())
#define spa << " " <<
#define fi first
#define se second
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define EB emplace_back
#define rep(i,n,m) for(ll i = (n); i < (ll)(m); i++)
#define rrep(i,n,m) for(ll i = (ll)(m) - 1; i >= (ll)(n); i--)

namespace template_tute{
  using ll = long long;
  using ld = long double;
  const ll MOD1 = 1e9+7;
  const ll MOD9 = 998244353;
  const ll INF = 4.1e18;
  using P = pair<ll, ll>;
  template<typename T> using PQ = priority_queue<T>;
  template<typename T> using QP = priority_queue<T,vector<T>,greater<T>>;
  template<typename T1, typename T2>bool chmin(T1 &a,T2 b){if(a>b){a=b;return true;}else return false;}
  template<typename T1, typename T2>bool chmax(T1 &a,T2 b){if(a<b){a=b;return true;}else return false;}
  ll median(ll a,ll b, ll c){return a+b+c-max<ll>({a,b,c})-min<ll>({a,b,c});}
  void ans1(bool x){if(x) cout<<"Yes"<<endl;else cout<<"No"<<endl;}
  void ans2(bool x){if(x) cout<<"YES"<<endl;else cout<<"NO"<<endl;}
  void ans3(bool x){if(x) cout<<"Yay!"<<endl;else cout<<":("<<endl;}
  template<typename T1,typename T2>void ans(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}  
  template<typename T1,typename T2,typename T3>void anss(T1 x,T2 y,T3 z){ans(x!=y,x,z);};  
  template<typename T>void debug(const T &v,ll h,ll w,string sv=" "){for(ll i=0;i<h;i++){cout<<v[i][0];for(ll j=1;j<w;j++)cout<<sv<<v[i][j];cout<<endl;}};
  template<typename T>void debug(const T &v,ll n,string sv=" "){if(n!=0)cout<<v[0];for(ll i=1;i<n;i++)cout<<sv<<v[i];cout<<endl;};
  template<typename T>void debug(const vector<T>&v){debug(v,v.size());}
  template<typename T>void debug(const vector<vector<T>>&v){for(auto &vv:v)debug(vv,vv.size());}
  template<typename T>void debug(stack<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
  template<typename T>void debug(queue<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop();}cout<<endl;}
  template<typename T>void debug(deque<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop_front();}cout<<endl;}
  template<typename T>void debug(PQ<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
  template<typename T>void debug(QP<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
  template<typename T>void debug(const set<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}
  template<typename T>void debug(const multiset<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}
  template<typename T,size_t size>void debug(const array<T, size> &a){for(auto z:a)cout<<z<<" ";cout<<endl;}
  template<typename T,typename V>void debug(const map<T,V>&v){for(auto z:v)cout<<"["<<z.first<<"]="<<z.second<<",";cout<<endl;}
  template<typename T>vector<vector<T>>vec(ll x, ll y, T w){vector<vector<T>>v(x,vector<T>(y,w));return v;}
  vector<ll>dx={1,-1,0,0,1,1,-1,-1};vector<ll>dy={0,0,1,-1,1,-1,1,-1};
  template<typename T>vector<T> make_v(size_t a,T b){return vector<T>(a,b);}
  template<typename... Ts>auto make_v(size_t a,Ts... ts){return vector<decltype(make_v(ts...))>(a,make_v(ts...));}
  template<typename T1, typename T2>ostream &operator<<(ostream &os, const pair<T1, T2>&p){return os << "(" << p.first << "," << p.second << ")";}
  template<typename T>ostream &operator<<(ostream &os, const vector<T> &v){os<<"[";for(auto &z:v)os << z << ",";os<<"]"; return os;}
  template<typename T>void rearrange(vector<int>&ord, vector<T>&v){
    auto tmp = v;
    for(int i=0;i<tmp.size();i++)v[i] = tmp[ord[i]];
  }
  template<typename Head, typename... Tail>void rearrange(vector<int>&ord,Head&& head, Tail&&... tail){
    rearrange(ord, head);
    rearrange(ord, tail...);
  }
  template<typename T> vector<int> ascend(const vector<T>&v){
    vector<int>ord(v.size());iota(ord.begin(),ord.end(),0);
    sort(ord.begin(),ord.end(),[&](int i,int j){return make_pair(v[i],i)<make_pair(v[j],j);});
    return ord;
  }
  template<typename T> vector<int> descend(const vector<T>&v){
    vector<int>ord(v.size());iota(ord.begin(),ord.end(),0);
    sort(ord.begin(),ord.end(),[&](int i,int j){return make_pair(v[i],-i)>make_pair(v[j],-j);});
    return ord;
  }
  template<typename T> vector<T> inv_perm(const vector<T>&ord){
    vector<T>inv(ord.size());
    for(int i=0;i<ord.size();i++)inv[ord[i]] = i;
    return inv;
  }
  ll FLOOR(ll n,ll div){assert(div>0);return n>=0?n/div:(n-div+1)/div;}
  ll CEIL(ll n,ll div){assert(div>0);return n>=0?(n+div-1)/div:n/div;}
  ll digitsum(ll n){ll ret=0;while(n){ret+=n%10;n/=10;}return ret;}
  ll modulo(ll n,ll d){return (n%d+d)%d;};
  template<typename T>T min(const vector<T>&v){return *min_element(v.begin(),v.end());}
  template<typename T>T max(const vector<T>&v){return *max_element(v.begin(),v.end());}
  template<typename T>T acc(const vector<T>&v){return accumulate(v.begin(),v.end(),T(0));};
  template<typename T>T reverse(const T &v){return T(v.rbegin(),v.rend());};
  //mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());
  int popcount(ll x){return __builtin_popcountll(x);};
  int poplow(ll x){return __builtin_ctzll(x);};
  int pophigh(ll x){return 63 - __builtin_clzll(x);};
  template<typename T>T poll(queue<T> &q){auto ret=q.front();q.pop();return ret;};
  template<typename T>T poll(priority_queue<T> &q){auto ret=q.top();q.pop();return ret;};
  template<typename T>T poll(QP<T> &q){auto ret=q.top();q.pop();return ret;};
  template<typename T>T poll(stack<T> &s){auto ret=s.top();s.pop();return ret;};
  ll MULT(ll x,ll y){if(LLONG_MAX/x<=y)return LLONG_MAX;return x*y;}
  ll POW2(ll x, ll k){ll ret=1,mul=x;while(k){if(mul==LLONG_MAX)return LLONG_MAX;if(k&1)ret=MULT(ret,mul);mul=MULT(mul,mul);k>>=1;}return ret;}
  ll POW(ll x, ll k){ll ret=1;for(int i=0;i<k;i++){if(LLONG_MAX/x<=ret)return LLONG_MAX;ret*=x;}return ret;}
  std::ostream &operator<<(std::ostream &dest, __int128_t value) {
    std::ostream::sentry s(dest);
    if (s) {
      __uint128_t tmp = value < 0 ? -value : value;
      char buffer[128];
      char *d = std::end(buffer);
      do {
        --d;
        *d = "0123456789"[tmp % 10];
        tmp /= 10;
      } while (tmp != 0);
      if (value < 0) {
        --d;
        *d = '-';
      }
      int len = std::end(buffer) - d;
      if (dest.rdbuf()->sputn(d, len) != len) {
        dest.setstate(std::ios_base::badbit);
      }
    }
    return dest;
  }
  namespace converter{
    int dict[500];
    const string lower="abcdefghijklmnopqrstuvwxyz";
    const string upper="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    const string digit="0123456789";
    const string digit1="123456789";
    void regi_str(const string &t){
      for(int i=0;i<t.size();i++){
        dict[t[i]]=i;
      }
    }
    void regi_int(const string &t){
      for(int i=0;i<t.size();i++){
        dict[i]=t[i];
      }
    }
    vector<int>to_int(const string &s,const string &t){
      regi_str(t);
      vector<int>ret(s.size());
      for(int i=0;i<s.size();i++){
        ret[i]=dict[s[i]];
      }
      return ret;
    }
    vector<int>to_int(const string &s){
      auto t=s;
      sort(t.begin(),t.end());
      t.erase(unique(t.begin(),t.end()),t.end());
      return to_int(s,t);
    }
    
    vector<vector<int>>to_int(const vector<string>&s,const string &t){
      regi_str(t);
      vector<vector<int>>ret(s.size(),vector<int>(s[0].size()));
      for(int i=0;i<s.size();i++){
        for(int j=0;j<s[0].size();j++){
          ret[i][j]=dict[s[i][j]];
        }
      }
      return ret;
    }
    vector<vector<int>>to_int(const vector<string>&s){
      string t;
      for(int i=0;i<s.size();i++){
        t+=s[i];
      }
      sort(t.begin(),t.end());t.erase(unique(t.begin(),t.end()),t.end());
      return to_int(s,t);
    }
    string to_str(const vector<int>&s,const string &t){
      regi_int(t);
      string ret;
      for(auto z:s)ret+=dict[z];
      return ret;
    }
    vector<string> to_str(const vector<vector<int>>&s,const string &t){
      regi_int(t);
      vector<string>ret(s.size());
      for(int i=0;i<s.size();i++){
        for(auto z:s[i])ret[i]+=dict[z];
      }
      return ret;
    }
  }
  template< typename T = int >
  struct edge {
    int to;
    T cost;
    int id;
    edge():to(-1),id(-1){};
    edge(int to, T cost = 1, int id = -1):to(to), cost(cost), id(id){}
    operator int() const { return to; }
  };

  template<typename T>
  using Graph = vector<vector<edge<T>>>;
  template<typename T>
  Graph<T>revgraph(const Graph<T> &g){
    Graph<T>ret(g.size());
    for(int i=0;i<g.size();i++){
      for(auto e:g[i]){
        int to = e.to;
        e.to = i;
        ret[to].push_back(e);
      }
    }
    return ret;
  }
  template<typename T>
  Graph<T> readGraph(int n,int m,int indexed=1,bool directed=false,bool weighted=false){
    Graph<T> ret(n);
    for(int es = 0; es < m; es++){
      int u,v;
      T w=1;
      cin>>u>>v;u-=indexed,v-=indexed;
      if(weighted)cin>>w;
      ret[u].emplace_back(v,w,es);
      if(!directed)ret[v].emplace_back(u,w,es);
    }
    return ret;
  }
  template<typename T>
  Graph<T> readParent(int n,int indexed=1,bool directed=true){
    Graph<T>ret(n);
    for(int i=1;i<n;i++){
      int p;cin>>p;
      p-=indexed;
      ret[p].emplace_back(i);
      if(!directed)ret[i].emplace_back(p);
    }
    return ret;
  }
}
using namespace template_tute;

using I = long long;
struct Point{
  I x, y;
  Point(): x(0), y(0){}
  Point(I x,I y):x(x),y(y){}
  Point &operator+=(const Point &p){
    x += p.x, y += p.y;
    return *this;
  }
  Point &operator-=(const Point &p){
    x -= p.x, y -= p.y;
    return *this;
  }
  Point &operator*=(I v){
    x *= v, y *= v;
    return *this;
  }
  Point &operator/=(I v){
    assert(x % v == 0 && y % v == 0);
    x /= v, y /= v;
    return *this;
  }
  friend Point operator+(const Point &l, const Point &r){
    return Point(l) += r;
  }
  friend Point operator-(const Point &l, const Point &r){
    return Point(l) -= r;
  }
  friend Point operator*(const Point &l, I r){
    return Point(l) *= r;
  }
  friend Point operator/(const Point &l, I r){
    return Point(l) /= r;
  }
  bool operator<(const Point &p)const{
    if(x == p.x)return y < p.y;
    return x < p.x;
  }
  bool operator>(const Point &p) const{
    if(x == p.x)return y > p.y;
    return x > p.x;
  }
  bool operator==(const Point &p)const{return x == p.x && y == p.y;}
  bool operator!=(const Point &p)const{return x != p.x || y != p.y;}
  friend ostream &operator<<(ostream &os, const Point &p) {
    return os << "(" << p.x << "," << p.y << ")";
  }
  friend istream &operator>>(istream &is, Point &p) {
    is >> p.x >> p.y;
    return (is);
  }

};

struct Line{
  Point a,b;
  Line() = default;
  Line(Point a, Point b) : a(a), b(b){}
};

I norm(const Point &p){
  return p.x * p.x + p.y * p.y;
}

I dot(const Point &a, const Point &b){
  return a.x * b.x + a.y * b.y;
}

I cross(const Point &a, const Point &b){
  return a.x * b.y - a.y * b.x;
}

I distance(const Point &a, const Point &b){
  return norm(a - b);
}
I area(const Point &a,const Point &b,const Point &c){
  return abs(cross(b-a,c-a));
}
constexpr int COUNTER_CLOCKWISE = +1;
constexpr int CLOCKWISE = -1;
constexpr int ONLINE_BACK = +2; // c-a-b
constexpr int ONLINE_FRONT = -2; // a-b-c
constexpr int ON_SEGMENT = 0; // a-c-b

int ccw(const Point &a, Point b, Point c) {
  b = b - a, c = c - a;
  if(cross(b, c) > 0) return COUNTER_CLOCKWISE;
  if(cross(b, c) < 0) return CLOCKWISE;
  if(dot(b, c) < 0) return ONLINE_BACK;
  if(norm(b) < norm(c)) return ONLINE_FRONT;
  return ON_SEGMENT;
}

bool parallel(const Line &a, const Line &b){
  return cross(a.b - a.a, b.b - b.a) == 0;
}

bool orthogonal(const Line &a, const Line &b){
  return dot(a.a - a.b, b.a - b.b) == 0;
}

bool argument_compare(Point a, Point b){
  if(a.x == 0 && a.y == 0)a.x = 1;
  if(b.x == 0 && b.y == 0)b.x = 1;
  if(a.y < 0 && b.y >= 0){
    return true;
  }
  else if(a.y >= 0 && b.y < 0){
    return false;
  }
  else if(a.y == 0 && b.y == 0){
    return a.x >= 0 && b.x < 0;
  }
  return cross(a, b) > 0;
}

vector<Point>convex_hull(const vector<Point>&points, bool onEdge = false){
  int n = points.size(), k = 0;
  auto p = points;
  const I limit = onEdge ? 0 : 1;
  if(n <= 2)return p;
  sort(p.begin(), p.end());
  vector<Point> ch(2 * n);
  for(int i = 0; i < n; ch[k++] = p[i++]) {
    while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < limit) --k;
  }
  for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {
    while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < limit) --k;
  }
  ch.resize(k - 1);
  return ch;
}
vector<Point>lower_convex_hull(const vector<Point>&points, bool onEdge = false){
  int n = points.size(), k = 0;
  auto p = points;
  const I limit = onEdge ? 0 : 1;
  if(n <= 2)return p;
  sort(p.begin(), p.end());
  vector<Point> ch(2 * n);
  for(int i = 0; i < n; ch[k++] = p[i++]) {
    while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < limit) --k;
  }
  ch.resize(k);
  return ch;
}
//各b_jに対して、cross(a_i,b_j)の最大値を求める
vector<I>get_cross_max(vector<Point>a,vector<Point>b){
  a = convex_hull(a, false);
  vector<int>ord(b.size());
  iota(ord.begin(),ord.end(),0);
  sort(ord.begin(),ord.end(),[&](int i,int j){return argument_compare(b[i],b[j]);});
  vector<I>ret(b.size());
  if(norm(b[ord[0]]) == 0 && norm(b[ord.back()]) == 0){
    return ret;
  }
  int start = 0;
  while(norm(b[ord[start]]) == 0)start++;
  int max_arg = 0;
  for(int i = 1; i < a.size(); i++){
    if(cross(a[max_arg], b[ord[start]]) < cross(a[i], b[ord[start]])){
      max_arg = i;
    }
  }
  for(auto i:ord){
    while(1){
      I c0 = cross(a[(max_arg == 0 ? a.size() - 1 : max_arg - 1)],b[i]);
      I c1 = cross(a[max_arg],b[i]);
      I c2 = cross(a[(max_arg == a.size() - 1 ? 0 : max_arg + 1)],b[i]);
      if(c0 <= c1 && c1 >= c2)break;
      max_arg++;
      if(max_arg >= a.size())max_arg -= a.size();
    }
    ret[i] = cross(a[max_arg], b[i]);
  }
  return ret;
}
vector<I>get_cross_min(vector<Point>a,vector<Point>b){
  for(auto &p:b)p *= -1;
  auto ret = get_cross_max(a, b);
  for(auto &r:ret)r *= -1;
  return ret;
}
vector<I>get_dot_max(vector<Point>a,vector<Point>b){
  for(auto &p:b){
    p = Point(-p.y, p.x);
  }
  auto ret=get_cross_max(a,b);
  return ret;
}
// 多角形と点の包含判定
enum {
  OUT, ON, IN
};
using Polygon=vector<Point>;
int contains(const Polygon &Q, const Point &p) {
  bool in = false;
  for(int i = 0; i < Q.size(); i++) {
    Point a = Q[i] - p, b = Q[(i + 1) % Q.size()] - p;
    if(a.y > b.y) swap(a, b);
    if(a.y <= 0 && 0 < b.y && cross(a, b) < 0) in = !in;
    if(cross(a, b) == 0 && dot(a, b) <= 0) return ON;
  }
  return in ? IN : OUT;
}

bool segment_intersect(const Line &s, const Line &t) {
  return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0;
}

bool segment_point_intersect(const Line &s, const Point &p) {
  return ccw(s.a, s.b, p) == 0;
}

void solve(){
	ll res=0,buf=0;
  bool judge = true;

  ll n,k;cin>>n>>k;
  vector<Point>p(n); 
  rep(i,0,n)cin>>p[i];
  ld pi=acos(-1);
  if(n==k){
    cout<<2*pi<<endl;
    return;
  }
  sort(ALL(p),argument_compare);
  ld ret=0;
  rep(i,0,n){
    auto l=p[i],r=p[(i+k)%n];
    auto lc=atan2(l.y,l.x),rc=atan2(r.y,r.x);
    if(lc>rc)rc+=2*pi;
    chmax(ret,rc-lc);
  }
  cout<<ret<<endl;
}

int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  ll res=0,buf=0;
  bool judge = true;
  int T = 1;
  cin>>T;
  lfs;
  while(T--){
    solve();
  }
  return 0;
}