#include <bits/stdc++.h>
#pragma GCC target("sse4,tune=native")
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;
template <typename T1, typename T2>
inline void chkmin(T1 &x, T2 y) {
  if (x > y) x = y;
}
template <typename T1, typename T2>
inline void chkmax(T1 &x, T2 y) {
  if (x < y) x = y;
}
template <typename T, typename U>
inline ostream &operator<<(ostream &_out, const pair<T, U> &_p) {
  _out << _p.first << ' ' << _p.second;
  return _out;
}
template <typename T, typename U>
inline istream &operator>>(istream &_in, pair<T, U> &_p) {
  _in >> _p.first >> _p.second;
  return _in;
}
template <typename T>
inline ostream &operator<<(ostream &_out, const vector<T> &_v) {
  if (_v.empty()) {
    return _out;
  }
  _out << _v.front();
  for (auto _it = ++_v.begin(); _it != _v.end(); ++_it) {
    _out << ' ' << *_it;
  }
  return _out;
}
template <typename T>
inline istream &operator>>(istream &_in, vector<T> &_v) {
  for (auto &_i : _v) {
    _in >> _i;
  }
  return _in;
}
template <typename T>
inline ostream &operator<<(ostream &_out, const set<T> &_s) {
  if (_s.empty()) {
    return _out;
  }
  _out << *_s.begin();
  for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) {
    _out << ' ' << *_it;
  }
  return _out;
}
template <typename T>
inline ostream &operator<<(ostream &_out, const multiset<T> &_s) {
  if (_s.empty()) {
    return _out;
  }
  _out << *_s.begin();
  for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) {
    _out << ' ' << *_it;
  }
  return _out;
}
template <typename T>
inline ostream &operator<<(ostream &_out, const unordered_set<T> &_s) {
  if (_s.empty()) {
    return _out;
  }
  _out << *_s.begin();
  for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) {
    _out << ' ' << *_it;
  }
  return _out;
}
template <typename T>
inline ostream &operator<<(ostream &_out, const unordered_multiset<T> &_s) {
  if (_s.empty()) {
    return _out;
  }
  _out << *_s.begin();
  for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) {
    _out << ' ' << *_it;
  }
  return _out;
}
template <typename T, typename U>
inline ostream &operator<<(ostream &_out, const map<T, U> &_m) {
  if (_m.empty()) {
    return _out;
  }
  _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')';
  for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) {
    _out << ", (" << _it->first << ": " << _it->second << ')';
  }
  return _out;
}
template <typename T, typename U>
inline ostream &operator<<(ostream &_out, const unordered_map<T, U> &_m) {
  if (_m.empty()) {
    return _out;
  }
  _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')';
  for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) {
    _out << ", (" << _it->first << ": " << _it->second << ')';
  }
  return _out;
}
const string FILENAME = "input";
const int MAXN = 100228;
const double Pi = acos(-1);
int n;
long double xx, yy;
long double v, t, rr;
long double x[MAXN], y[MAXN], r[MAXN];
long double l, ans;
vector<pair<long double, long double> > p;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  l = -Pi;
  cin >> xx >> yy >> v >> t >> n;
  rr = v * t;
  for (int i = 0; i < n; i++) {
    int as, bs, cs;
    cin >> as >> bs >> cs;
    x[i] = as;
    y[i] = bs;
    r[i] = cs;
    x[i] -= xx;
    y[i] -= yy;
    if (sqrt(x[i] * x[i] + y[i] * y[i]) <= r[i]) {
      cout << 1 << '\n';
      return 0;
    }
    long double L, R, a;
    long double dd = sqrt(x[i] * x[i] + y[i] * y[i]);
    if (dd >= r[i] + rr) {
      continue;
    }
    L = atan2(y[i], x[i]);
    a = sqrt(x[i] * x[i] + y[i] * y[i] - r[i] * r[i]);
    if (a <= rr) {
      R = asin(r[i] / dd);
    } else {
      R = acos((dd * dd + rr * rr - r[i] * r[i]) / (2 * dd * rr));
    }
    L -= R;
    R = L + R * 2;
    if (L < -Pi) {
      p.push_back({L + 2 * Pi, Pi});
      L = -Pi;
    }
    if (R > Pi) {
      p.push_back({-Pi, R - 2 * Pi});
      R = Pi;
    }
    p.push_back({L, R});
  }
  sort((p).begin(), (p).end());
  for (auto x : p) {
    if (l < x.first) {
      l = x.first;
    }
    if (x.second <= l) {
      continue;
    }
    ans += x.second - l;
    l = x.second;
  }
  cout.precision(18);
  cout << fixed << (double)ans / (2 * Pi) << endl;
  return 0;
}
