Răspuns:
#include<iostream>
using namespace std;
int main() {
int xa, ya, xb, yb, xo = 0, yo = 0;
float A,CM,AB,AO,BO;
cout << "xA= ";
cin >> xa;
cout << "yA= ";
cin >> ya;
cout << "xB= ";
cin >> xb;
cout << "yB= ";
cin >> yb;
AO = (sqrt(pow(xa - xo, 2) + pow(ya - yo, 2)));
BO = (sqrt(pow(xb - xo, 2) + pow(yb - yo, 2)));
AB = (sqrt(pow(xa - xb, 2) + pow(ya - yb, 2)));
A = AO * BO;
CM = AO * BO;
cout << "P=" << AO + BO + AB<<"\n";
cout << "A=" << A/ 2 << "\n";
cout << "CM=" << CM / AB << "\n";
}