#include<cmath>
#include<cstdio>
#include<vector>
#include<algorithm>
 
#define rep(i,n) for(int i=0;i<(n);i++)
 
using namespace std;
 
const double EPS=1e-7;
const double PI=acos(-1);
 
template<class T>
struct point{
    T x,y;
    point operator+(const point &a)const{ return (point){x+a.x,y+a.y}; }
    point operator-(const point &a)const{ return (point){x-a.x,y-a.y}; }
};
 
template<class T>
point<T> operator*(T c,const point<T> &a){ return (point<T>){c*a.x,c*a.y}; }
 
bool operator==(const point<double> &a,const point<double> &b){
    return abs(a.x-b.x)<EPS && abs(a.y-b.y)<EPS;
}
 
template<class T>
double abs(const point<T> &a){ return sqrt(a.x*a.x+a.y*a.y); }
 
template<class T>
T cross(const point<T> &a,const point<T> &b){ return a.x*b.y-a.y*b.x; }
 
point<double> rot(const point<double> &a,double theta){
    return (point<double>){a.x*cos(theta)-a.y*sin(theta),a.x*sin(theta)+a.y*cos(theta)};
}
 
template<class T>
double arg(const point<T> &a){
    double t=atan2(a.y,a.x);
    return t<0?t+2*PI:t;
}
 
template<class T>
struct segment{ point<T> a,b; };
 
enum{CCW=1,CW=-1,ON=0};
int ccw(const point<double> &a,const point<double> &b,const point<double> &c){
    double rdir=cross(b-a,c-a);
    if(rdir> EPS) return CCW;
    if(rdir<-EPS) return CW;
    return ON;
}
 
template<class T>
double dist(const point<T> &a,const point<T> &b){
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
 
bool cover(const segment<double> &S,const point<double> &p){
    return dist(S.a,p)+dist(p,S.b)<dist(S.a,S.b)+EPS;
}
 
bool intersect(const segment<double> &S1,const segment<double> &S2){
    if(max(S1.a.x,S1.b.x)+EPS<min(S2.a.x,S2.b.x)
    || max(S1.a.y,S1.b.y)+EPS<min(S2.a.y,S2.b.y)
    || max(S2.a.x,S2.b.x)+EPS<min(S1.a.x,S1.b.x)
    || max(S2.a.y,S2.b.y)+EPS<min(S1.a.y,S1.b.y)) return false;
    return ccw(S1.a,S1.b,S2.a)*ccw(S1.a,S1.b,S2.b)<=0
        && ccw(S2.a,S2.b,S1.a)*ccw(S2.a,S2.b,S1.b)<=0;
}
 
point<double> get_intersect(const segment<double> &S1,const segment<double> &S2){
    double a1=cross(S1.b-S1.a,S2.b-S2.a);
    double a2=cross(S1.b-S1.a,S1.b-S2.a);
    if(abs(a1)<EPS){
        if(cover(S1,S2.a)) return S2.a;
        if(cover(S1,S2.b)) return S2.b;
        if(cover(S2,S1.a)) return S1.a;
        return S1.b;
    }
    return S2.a+a2/a1*(S2.b-S2.a);
}
 
int n,m,K;
point<double> P[50]; // ???
 
point<double> star[50]; // ???????????¨??? m ??????????????????
 
vector< pair<double,double> > in; // ?????????????????¨??????????????????????????????????????±. ??????????????????????????????????????? <?§????,????????????????????¢>
point<double> in2[100]; // ?\???§?¨???§???????????? in ?????´?????§?¨??????´???????????? ( ?????????????????? )
 
void get_intersect(const point<double> *G1,const point<double> *G2,int &sz,point<double> *res){
    segment<double> S1[50],S2[50]; // ?????????
    rep(i,m){
        S1[i].a=G1[i];
        S1[i].b=G1[(i+K)%m];
        S2[i].a=G2[i];
        S2[i].b=G2[(i+K)%m];
    }
    rep(i,m) rep(j,m) if(intersect(S1[i],S2[j])) res[sz++]=get_intersect(S1[i],S2[j]);
}
 
bool cover(double R,const point<double> &cen,const point<double> &p){
    if(p==cen) return true;
 
    double phi=arg(p-cen),d=dist(p,cen);
    if(d>R+EPS) return false;
 
    if(phi<in[0].first+EPS) phi+=2*PI;
    int i=upper_bound(in.begin(),in.end(),make_pair(phi,0.0))-in.begin()-1;
    return ccw(R*in2[i],R*in2[(i+1)%in.size()],p-cen)!=CW;
}
 
// p1, p2 : ???????¢????????????????????????????
bool check(double R,const point<double> &p1,const point<double> &p2){
    point<double> G1[50],G2[50]; // ?????????????????¢?????????, ???????????? p1, p2 ??????????????\???????????????????§????????????????
    rep(k,m){
        point<double> p=R*(point<double>){star[k].x,-star[k].y};
        G1[k]=p+p1;
        G2[k]=p+p2;
    }
 
    int sz=0;
    static point<double> Q[50*50]; // ???????????????????£????
    get_intersect(G1,G2,sz,Q);
    Q[sz++]=(point<double>){0,0}; // ???????????\???????????¨?????????
 
    rep(k,sz){
        bool ok=true;
        rep(l,n) if(!cover(R,Q[k],P[l])) { ok=false; break; }
        if(ok) return true;
    }
    return false;
}
 
int main(){
    for(;scanf("%d%d%d",&n,&m,&K),n;){
        rep(i,n) scanf("%lf%lf",&P[i].x,&P[i].y);
 
        rep(i,m) star[i]=rot((point<double>){1,0},2*i*PI/m+PI/2);
 
        in.clear();
        rep(i,m){
            in.push_back(make_pair(arg(star[i]),abs(star[i])));
            if(K>1){
                segment<double> S1={star[i],star[(i+K)%m]};
                segment<double> S2={star[(i+1)%m],star[(i+1-K+m)%m]};
                point<double> p=get_intersect(S1,S2);
                in.push_back(make_pair(arg(p),abs(p)));
            }
        }
        sort(in.begin(),in.end());
        rep(i,in.size()){
            in2[i].x=in[i].second*cos(in[i].first);
            in2[i].y=in[i].second*sin(in[i].first);
        }
 
        double ans=1e4;
        // p, q ????????? R1 ??????????¢??????¨???????????¨??§????????¨?????????, ?????? R2(>R1) ??????????¢????????????¨??§????????????????????????????????????(??¨??????)?????§??????????§£???
        rep(i,n) for(int j=i+1;j<n;j++) { // ???????¢????????????????????±??????????
            if(!check(ans+EPS,P[i],P[j])) continue; // ?§£??????????????????????????????????????§????????¢?´¢?????????
 
            double lo=0,hi=ans;
            while(hi-lo>1e-6){
                double mi=(lo+hi)/2;
                if(check(mi,P[i],P[j])) hi=mi; else lo=mi;
            }
            ans=(lo+hi)/2;
        }
 
        printf("%.9f\n",ans);
    }
 
    return 0;
}

Measured memory_bytes: 3144