#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define p_yes() p("YES")
#define p_no() p("NO")
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair

ll SUM(VI& V){
  return accumulate(ALL(V), 0LL);
}

void print_vector(VI& V){
  ll n = V.size();
  rep(i, n){
    if(i) cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

ll gcd(ll a,ll b){
    if(b == 0) return a;
    return gcd(b,a%b);
}

ll lcm(ll a,ll b){
    ll g = gcd(a,b);
    return a / g * b;
}

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

// snukeさんの幾何セット
const double eps = 1e-9;
bool equal(double a, double b) { return abs(a-b) < eps;}
struct V {
  double x, y;
  V(double x=0, double y=0) : x(x), y(y) {}
  V operator+(const V& p) const { return V(x+p.x, y+p.y);}
  V operator-(const V& p) const { return V(x-p.x, y-p.y);}
  V operator*(double a) const { return V(x*a, y*a);}
  double sqrNorm() const { return x*x+y*y;}
  double norm() const { return sqrt(sqrNorm());}
  V rotate90() const { return V(y, -x);}
};
struct Circle {
  V o; double r;
  Circle(V o=V(), double r=0) : o(o), r(r) {}
  vector<V> xp(const Circle& c) {
    V v = c.o-o;
    double l = v.norm();
    if (equal(l, 0)) return {};
    if (equal(l+r+c.r, max({l,r,c.r})*2)) {
      return {o + v*(r/l)};
    }
    if (l+r+c.r < max({l,r,c.r})*2) return {};
    double x = -(c.r*c.r - l*l - r*r) / (2*l);
    double y = sqrt(r*r - x*x);
    V mid = o + v*(x/l);
    v = v.rotate90();
    return {mid + v*(y/l), mid - v*(y/l)};
  }
  bool isInside(const V& p) {
    return (p-o).norm() < r+eps;
  }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N,K;
    cin>>N>>K;

    // コーナーケース
    if (K == 1) {
      cout << 0 << endl;
      return 0;
    }

    vector<Circle> C(N);
    rep(i,N){
      cin>>C[i].o.x >> C[i].o.y >> C[i].r; 
    }

    double l=0; //can't
    double r=400000;//can
    ll LOOP=100;
    while(LOOP--){
      double T = (l+r)/2; // T秒で焼けるか
      vector<V> ps; // points
      // 交点登録
      rep(i,N){
        FOR(j,i+1,N){
          auto a = C[i];
          auto b = C[j];
          // 半径を更新
          a.r = T/a.r;
          b.r = T/b.r;
          // 交点
          auto c = a.xp(b);
          ps.insert(ps.end(), c.begin(), c.end()); // vectorの挿入
        }
      }
      // 円の中心登録（円の中に円という場合を考慮）
      rep(i,N){
        ps.push_back(C[i].o);
      }
      bool ok=false;
      for(V p : ps){
        // 交点ｐ
        ll cnt=0;
        rep(i,N){
          // 各円から見て、ｐは円内か
          auto a = C[i];
          // 半径をTに合わせて調整
          a.r = T/a.r;
          if(a.isInside(p)){
            cnt++;
          }
        }
        if(cnt>=K) ok=true;
      }
      if(ok){
        r=T;
      }else{
        l=T;
      }
    }
    cout << setprecision(20);
    p(r);

    return 0;
}

Measured memory_bytes: 512