#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void umax(T &a, T b) {
  if (a < b) a = b;
}
const int maxn = (int)1e5 + 5;
const int INF = 1e9 + 7;
const double eps = 1e-10;
double PI = acos(-1);
int fi[maxn], si[maxn], r1, v1, dis1;
bool check(double t) {
  double dis = dis1;
  dis -= v1 * t;
  dis -= abs(2.0 * r1 * sin((v1 * t) / (2.0 * r1)));
  if (dis <= 0)
    return true;
  else
    return false;
}
inline void solve(void) {
  int n;
  cin >> n;
  cin >> r1 >> v1;
  for (int i = (0); i < (n); i++) {
    cin >> fi[i] >> si[i];
  }
  for (int i = (0); i < (n); i++) {
    double l = 0, r = 1e15;
    for (int it = (0); it < (100); it++) {
      dis1 = si[i] - fi[i];
      double mid = (l + r) / 2;
      if (check(mid)) {
        r = mid;
      } else
        l = mid;
    }
    cout << fixed << setprecision(13) << l << "\n";
  }
  return;
}
void init() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
}
int main(int argc, const char *argv[]) {
  init();
  solve();
  return 0;
}
