#include <bits/stdc++.h>
using namespace std;
const double delta = 1e-8;
const int maxm = 1e5 + 10;
const double pi = acos(-1.0);
struct point {
  long long x, y, r, d2, r2;
  double d;
} s[maxm];
struct self {
  double l, r;
  self(double ll = 0, double rr = 0) {
    l = ll;
    r = rr;
  }
  bool operator<(const self &head) const {
    return head.l == l ? head.r < r : head.l > l;
  }
};
vector<self> ans;
int m, n;
long long x, y, v, t;
long long sqr(long long u) { return u * u; }
double sqr(double u) { return u * u; }
int flag;
long long r;
double r2;
double newr2;
double ll, rr, tot;
int main() {
  scanf("%I64d%I64d%I64d%I64d", &x, &y, &v, &t);
  r = v * t;
  r2 = 1.0 * r * r;
  scanf("%d", &m);
  for (int i = 1; i <= m; i++) {
    scanf("%I64d%I64d%I64d", &s[i].x, &s[i].y, &s[i].r);
    s[i].x -= x;
    s[i].y -= y;
    s[i].r2 = s[i].r * s[i].r;
    s[i].d2 = sqr(s[i].x) + sqr(s[i].y);
    s[i].d = sqrt(1.0 * s[i].d2);
    if (s[i].d2 <= s[i].r2) flag = 1;
  }
  if (flag)
    printf("1\n");
  else {
    for (int i = 1; i <= m; i++) {
      if (r + s[i].r < s[i].d) continue;
      if (r2 > s[i].d2 - s[i].r2)
        newr2 = s[i].d2 - s[i].r2;
      else
        newr2 = r2;
      double base = atan2(s[i].y, s[i].x);
      if (base < 0) base += 2 * pi;
      double alpha =
          acos((newr2 + s[i].d2 - s[i].r2) / (2 * sqrt(newr2) * s[i].d));
      double ll = base - alpha;
      double rr = base + alpha;
      if (ll < 0) {
        ans.push_back(self(ll + 2 * pi, 2 * pi));
        ll = 0;
      }
      if (rr > 2 * pi) {
        ans.push_back(self(0, rr - 2 * pi));
        rr = 2 * pi;
      }
      ans.push_back(self(ll, rr));
    }
    sort(ans.begin(), ans.end());
    if (ans.size() != 0) {
      ll = ans[0].l;
      rr = ans[0].r;
      for (int i = 1; i < ans.size(); i++) {
        if (ans[i].l > rr) {
          tot += rr - ll;
          ll = ans[i].l;
          rr = ans[i].r;
        } else if (ans[i].r > rr)
          rr = ans[i].r;
      }
      tot += rr - ll;
    } else
      tot = 0;
    printf("%.8f\n", tot / 2 / pi);
  }
  return 0;
}
