#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(center, C);
    if (distance < radi * radi + EPS) {
      cout << "1.00000";
      return 0;
    }
    if (sqrt(distance) - EPS > 1.00 * radi + 1.00 * R) continue;
    double angletocenter =
        atan2(center.second - C.second, center.first - C.first);
    if (angletocenter < 0) angletocenter += 2 * PI;
    double tangent_length = sqrt(distance - (1.00 * radi * radi));
    double diverge_angle;
    if (tangent_length < R + EPS) {
      diverge_angle = asin(radi / sqrt(distance));
    } else {
      diverge_angle = acos((distance + 1.00 * R * R - 1.0 * radi * radi) /
                           (2 * sqrt(distance) * 1.00 * R));
    }
    double left = angletocenter - diverge_angle;
    double right = angletocenter + diverge_angle;
    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({right - 2 * PI, -1});
      cut.push_back({0.00, 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));
}
