#include <bits/stdc++.h>   using namespace std;   using ll = long long;   long double r, v;   long double eps = 1e-8;   const long double mpi = acos(-1.0);   inline long double dist(long double theta) {     return 2.0L * r * (sin(theta) + theta);   }   inline double ti(long double theta, long long ni) {     return 2.0L * r * (mpi * ni + theta) / v;   }   void solve() {     int si, fi;     scanf( %d%d , &si, &fi);     long double d = fi - si;     long long ni = d / (2.0L * mpi * r);     long double left = 0;     long double right = mpi;     d -= 2.0L * r * mpi * ni;     long double dleft = dist(left);     long double dright = dist(right);     long double e = eps * v;     while (dright - dleft > e) {       long double mid = (right + left) / 2.0L;       long double dmid = dist(mid);       if (dmid > d) {         right = mid;         dright = dmid;       } else {         left = mid;         dleft = dmid;       }     }     double res = ti(right, ni);     printf( %.10f n , res);     return;   }   int main() {     int n, ri, vi;     scanf( %d%d%d , &n, &ri, &vi);     r = ri;     v = vi;     while (n--) {       solve();     }     cout.flush();     return 0;   }   