- 一级,还是一级(第4轮)
 111
- @ 2023-8-3 13:50:05
 
#include <bits/stdc++.h>
using namespace std;
int main()
{
    double r,a,b,c,pi;
    pi=3.14159;
    cin>>r;
    a=2*r;
    b=2*pi*r;
    c=pi*r*r;
    printf("%.4lf %.4lf %.4lf\n",a,b,c);
    return 0;
}
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