AC ❤ · 发布于 2025-08-10 · 浏览 342 回复 0 include <bits/stdc++.h> using namespace std; double r, l, c, s; int main() { cin >> r; printf("%.4lf %.4lf %.4lf", 2 * r, 2 * r * 3.1415926, 3.1415926 * r * r); return 0; }