#include <iostream> #include <iomanip> #include <math.h> using namespace std; int main(void) { double a, b, c, circumference, area, p;; cin>>a>>b>>c; circumference = a+b+c; p = (a+b+c) / 2; area = sqrt(p*(p-a)*(p-b)*(p-c)); cout<<"circumference="<<fixe...