#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const double EPS = 1e-9;
long long dis(pair<long long, long long> a, pair<long long, long long> b) {
  return (a.first - b.first) * (a.first - b.first) +
         (a.second - b.second) * (a.second - b.second);
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long T, v;
  pair<long long, long long> C;
  cin >> C.first >> C.second >> v >> T;
  long long R = 1.00 * v * T;
  long long n;
  cin >> n;
  vector<pair<double, long long> > cut;
  pair<long long, long long> center;
  long long radi;
  for (long long i = 0; i < n; i++) {
    cin >> center.first >> center.second >> radi;
    double distance = dis(C, center);
    if (distance < 1.0 * radi * radi + EPS) {
      cout << "1.00000";
      return 0;
    }
    distance = sqrt(distance);
    if (1.00 * radi + R * 1.00 < distance - EPS) continue;
    double left, right, ang;
    double angM = atan2(center.second - C.second, center.first - C.first);
    if (angM < 0) {
      angM += 2 * PI;
    }
    double tLen = sqrt(distance * distance - 1.0 * radi * radi);
    if (tLen < R + EPS) {
      ang = asin(radi / distance);
    } else {
      ang = acos((distance * distance + 1.00 * R * R - 1.0 * radi * radi) /
                 (2 * distance * 1.00 * R));
    }
    left = angM - ang;
    right = angM + ang;
    if (left < 0) {
      cut.push_back({left + 2 * PI, 1});
      cut.push_back({2 * PI, -1});
      cut.push_back({0.00, 1});
      cut.push_back({right, -1});
    } else if (right > 2 * PI) {
      cut.push_back({left, 1});
      cut.push_back({2 * PI, -1});
      cut.push_back({0.00, 1});
      cut.push_back({right - 2 * PI, -1});
    } else
      cut.push_back({left, 1}), cut.push_back({right, -1});
  }
  double ans = 0.00;
  long long count = 0;
  double last = 0;
  sort(cut.begin(), cut.end());
  for (auto &x : cut) {
    if (count > 0) ans += (x.first - last);
    last = x.first;
    count += (x.second);
  }
  cout << fixed << setprecision(6) << (ans / (2 * PI));
}
