#include <iostream>
#include <math.h>

using namespace std;

int main() {
	int x1,y1,x2,y2,x3,y3;
	float a,b,c,s,p;
	cout<<"Nhap toa do A(x1, y1): "; cin>>x1>>y1;
	cout<<"Nhap toa do B(x2, y2): "; cin>>x2>>y2;
	cout<<"Nhap toa do C(x3, y3): "; cin>>x3>>y3;
	a = sqrt(pow(x2-x1,2)+pow(y2-y1,2)); //AB
	b = sqrt(pow(x3-x2,2)+pow(y3-y2,2)); //BC
	c = sqrt(pow(x3-x1,2)+pow(y3-y1,2)); //CA
	cout<<"Do dai AB = "<<a<<endl;
	cout<<"Do dai BC = "<<b<<endl;
	cout<<"Do dai CA = "<<c<<endl;
	cout<<"Chu vi tam giac ABC la: "<<a+b+c<<endl;
	p = (a + b + c) / 2;
	s = sqrt(p * (p - a) * (p - b) * (p - c));
	cout<<"Dien tich tam giac ABC la: "<<s;
	return 0;
}