C :

#include "stdio.h"
#include "stdlib.h"
const double r = 5.3;
const double pi = 3.14159;
 
int main() {
    printf("Area=%.5f\n", r * r * pi / 2);
    printf("circumference=%.5f\n", 2 * r * pi / 2);
    return 0;
}