#include<stdio.h> #include<math.h> int main() { double s1,s2,s3; double zhouchang,mianji,t; scanf("%lf",&s1); scanf("%lf",&s2); scanf("%lf",&s3); zhouchang = s1+s2+s3; t = zhouchang/2; mianji=sqrt(t*(t-s1)(t-s2)(t-s3)); printf("circumference=%.2lf area=%.2lf",zhouchang,mianji); }