#include<iostream>
#include <math.h>
using namespace std;
bool checktamgiac (int a, int b, int c)
{
if ((a + b > c) && (a + c > b) && (b + c > 1))
return true;
return false;
}
float tinhdientichtg(int a, int b, int c)
{
float p = (float)(a + b + c) / 2;
float s = sqrt((p - a) + (p - b) + (p - c));
return s;
}
int main()
{
int a, b, c;
cout << "nhap a =" <<endl;
cin >> a;
cout << "nhap b =" << endl;
cin >> b;
cout << "nhap c =" << endl;
cin >> c;
if(checktamgiac(a,b,c)== true)
cout << "la mot tam giac co dien tich la" << tinhdientichtg(a, b, c);
else
cout << "khong phai la mot tam giac ";
return 0;
}