>>13
#include<stdio.h>
#include<math.h>
#define DATA_NUM 6
int main(void){
double x[DATA_NUM], y[DATA_NUM];
double sum_x, sum_y, ave_x, ave_y, dif_x, dif_y;
double S, X, Y, R, X_2, Y_2;
int i;
sum_x=0.0;sum_y=0.0;
for(i=0;i<DATA_NUM;i++){
scanf("%lf %lf", &x[i], &y[i]);
sum_x+=x[i];
sum_y+=y[i];
}
ave_x=sum_x/DATA_NUM;
ave_y=sum_y/DATA_NUM;
S=0.0;X_2=0.0;Y_2=0.0;
for(i=0;i<DATA_NUM;i++){
dif_x=x[i]-ave_x;
dif_y=y[i]-ave_y;
S+=dif_x*dif_y/DATA_NUM;
X_2+=dif_x*dif_x;
Y_2+=dif_y*dif_y;
}
X=sqrt(X_2);
Y=sqrt(Y_2);
R=S/(X*Y);
printf("%f\n", S);
printf("%f\n", R);
return 0;
}