#include <bits/stdc++.h>
using namespace std;
#define all(a) (a).begin(), (a).end()
#define double long double

const int maxn = 105;
const double maxc = 10000;
int x[maxn];
int y[maxn];
int c[maxn];

int n;

double f(double px, double py) {
    double ans = -1e9;
    for (int i = 0; i < n; ++i) {
        double dx = px - x[i];
        double dy = py - y[i];

        ans = max(ans, sqrt(dx*dx + dy*dy) * c[i]);
    }
    return ans;
}

double fx(double px) {
    double l = -maxc;
    double r =  maxc;
    for (int _ = 0; _ < 300; ++_) {
        double m1 = l + (r - l) / 3;
        double m2 = l + (r - l) / 3 * 2;

        double f1 = f(px, m1);
        double f2 = f(px, m2);
        if (f2 >= f1) {
            r = m2;
        } else {
            l = m1;
        }
    }
    return f(px, (r + l) / 2);
}

void solve() {
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> x[i] >> y[i] >> c[i];
    }

    double l = -maxc;
    double r =  maxc;
    for (int _ = 0; _ < 300; ++_) {
        double m1 = l + (r - l) / 3;
        double m2 = l + (r - l) / 3 * 2;

        double f1 = fx(m1);
        double f2 = fx(m2);
        if (f2 >= f1) {
            r = m2;
        } else {
            l = m1;
        }
    }
    cout << fx((r + l) / 2) << '\n';
}

signed main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cout.precision(10),cout.setf(ios_base::fixed);
    solve();
}