* Ngôn ngữ C :  #include <stdio.h>
#include <conio.h>
#include <math.h>
#define PI 3.14159
int main() {
            int r;
            float chuvi, dientich;
            printf("Nhap ban kinh r:");
            scanf("%d", &r);
            chuvi = 2*PI*r;
            dientich = PI*r*r;
            printf("Chu vi hinh tron la: %f\n", chuvi);
            printf("Dien tich hinh tron la: %f", dientich);
            getch(); }