655E

#include<bits/stdc++.h>
typedef long long ll;

typedef long double ld;
using namespace std;

int a[6283186];
const ld pi=acos(-1);

int main()
{

       /* while(1)
        {

            ld x,y;
            cin>>x>>y;
            cout<<atan2(x,y);
        }*/
    int x0,y0,v,t;
    cin>>x0>>y0>>v>>t;

    int n;

    cin>>n;
    for(int i=0;i<n;i++)
    {
        int x,y,r;
        cin>>x>>y>>r;
        x-=x0,y-=y0;
        ld d= hypot(x,y);
        if(d-r<=0){
            cout<<1;
            return 0;
        }
        if(d-r>v*t)continue;
        ld theta=atan2(y*1.0,x*1.0);
        if(theta<0)theta+=2*pi;
        ld psi =acos(r/d);
        int in,on;
        in =1e6*(theta-psi);
        on=1e6*(theta+psi);
        a[in]++;
        a[on]--;
       // cout<<in<<' '<<on<<endl;

    }
        ld h=0;
        int fl=0;
        for(int i=0;i<6283186;i++)
        {

            fl+=a[i];
            if(fl)h++;
        }
        ld ans=h/(2*pi*1e6);
        cout<<fixed(;
        cout.precision(8);
        cout<<ans;

    return 0;
}