Nicole · 发布于 2025-09-06 · 浏览 318 回复 0

#include <stdio.h>

int main() {
double a, r, c, s, d;
scanf("%lf %lf", &r);
a = 3.1415926;
d = r + r;
s = a * r * r;
c = a * d;
printf("%.4lf %.4lf %.4lf", d, c,s);
return 0;
}