#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  double f, s, v, l, omega, r;
  const double tol = 1.0e-7;
  scanf("%d %lf %lf", &n, &r, &v);
  omega = v / r;
  double xt, xb, a, b;
  for (int i = 0; i < n; i++) {
    scanf("%lf %lf", &s, &f);
    l = (f - s) / 2.;
    a = (l + r + 0.1) / v;
    b = -0.1;
    xt = (a + b) / 2.;
    while (abs((b - a) / xt) > tol) {
      if ((v * xt + r * sin(xt * omega) - l) *
              (v * a + r * sin(a * omega) - l) <
          0.)
        b = xt;
      else
        a = xt;
      xt = (a + b) / 2.;
    }
    a = (l + r + 0.1) / v;
    b = -0.1;
    do {
      xb = (a + b) / 2.;
      if ((v * xb - r * sin(xb * omega) - l) *
              (v * a - r * sin(a * omega) - l) <
          0.)
        b = xb;
      else
        a = xb;
    } while (abs((b - a) / xb) > tol);
    printf("%.10lf\n", 2. * min(xb, xt));
  }
  return 0;
}
