#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <string>
#include <stdio.h>
#include <algorithm>
#include <set>
#include <map>
#include <math.h>
#include <cmath>
#include <queue>
#include <iomanip>
#include <bitset>
#include <unordered_map>
#include <stack>
#include <memory.h>
#include <list>
#include <unordered_set>
#include <complex>
#include <cassert>
#include <numeric>
#include <functional>

#define ll long long
#define ld long double
#define ull unsigned ll
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define pii pair<int,int>
#define vi vector<int>
#define vpii vector<pii>
#define vvi vector<vector<int>>
#define endl '\n'
#define forn(it,from,to) for(int (it)=from; (it)<to; (it)++)
const ll  Inf = 1e18;
ll LINF = (ll)2e18;
using namespace std;
ll mod = 1e9 + 7;
ll mod3 = 998244353;
ll mod2 = 1e9 + 123;
#define M_PI       3.14159265358979323846   // pi

struct pt {
    ld  x, y;
};

ld get_dist(const pt &p1, const pt &p2) {
    return sqrt((p1.x - p2.x)*(p1.x - p2.x) + (p1.y - p2.y)*(p1.y - p2.y));
}

int main() {
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
    //freopen("javacert.in", "r", stdin);
    //freopen("javacert.out", "w", stdout);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0); cout.setf(ios::fixed); cout.precision(5);
    ld x1, y1, x2, y2;
    int n;
    cin >> x1 >> y1 >> x2 >> y2 >> n;
    ld k = (y2 - y1) / (x2 - x1);
    ld ans = 0;
    forn(i, 0, n) {
        ld x0, y0, r;
        cin >> x0 >> y0 >> r;
        //cout << x0 << " " << y0 << " " << r << endl;
        ld cc = x1 * k - y1 + y0;
        ld a = k * k + 1;
        ld b = -2.0 * cc*k - 2.0 * x0;
        ld c = cc * cc + x0 * x0 - r * r;
        cout << a << " " << b << " " << c << endl;
        ld d = b * b - 4.0 * a*c;
        if (d > 0) {
            ld x_1 = (-b - sqrt(d)) / (2.0 * a);
            ld x_2 = (-b + sqrt(d)) / (2.0 * a);
            ld y_1 = k * x_1 - x1 * k + y1;
            ld y_2 = k * x_2 - x1 * k + y1;
            if (x1 > x2) swap(x1, x2);
            if (y1 > y2) swap(y1, y2);
            if (x_1<x1 || x_1>x2 || x_2<x1 || x_2>x2) continue;
            ans += get_dist({ x_1, y_1 }, { x_2, y_2 });
        }
    }
    //cout << ans;
    return 0;
}