#define Circle_Area(r) (M_PI*r*r)
#define Circumference(r) (M_PI*2.00*r)
#define EPS(1E-5)

#include <stdio.h>
#include <math.h>

int main(void){
double radius;
for( radius = 0.1; radius<=4.0; radius += 0.1 ){
if( fabs(Circle_Area(radius) - Circumference(radius)) < EPS){
printf("Radius = %20.15lf \n",radius);
printf("Circle_Area = %20.15lf \n",Circle_Area(radius));
printf("Circumference = %20.15lf \n",Circumference(radius));
}
}
}