1)
#include
#include
#include
using namespace std;
signed main() {
double a,b,c;
cin >> a >> b >> c;
double p = (a+b+c)/2;
cout << sqrt(p * (p-a) * (p-b) * (p-c));</p>
}
2)
#include
#include
#include
using namespace std;
struct point{
double x;
double y;
};
double len(point a, point b)
{
return sqrt(pow(a.x-b.x,2) + pow(a.y-b.y,2));
}
signed main() {
point A,B,C;
cin >> A.x >> A.y >> B.x >> B.y >> C.x >> C.y;
double AB = len(A,B);
double AC = len(A,C);
double BC = len(B,C);
double p = (AB+BC+AC)/2;
cout << sqrt(p * (p-AB) * (p-BC) * (p-AC));</strong>
}