$\color{#1c1c1c}{\text{tu}}$$\color{#363636}{\text{a}}$$\color{#4f4f4f} {\text{n}}$$\color{#696969}{\text{d}}$$\color{#828282} {\text{u}}$$\color{#9c9c9c}{\text{n}}$$\color{#b5b5b5} {\text{m}}$$\color{#cfcfcf}{\text{a}}$$\color{#eee9e9}{\text{i}}$

#include<bits/stdc++.h>
using namespace std;

int main() {
    double a,b,c,p,t;
    cin>>a>>b>>c;
    if (a+b>c&&a+c>b&&b+c>a){
         p=(a+b+c)/2;
         t=sqrt(t*(t-a)*(t-b)*(t-c));
    }
    cout<<"Dien tich tam giac: "<<fixed<<setprecision(2)<<t;
return 0;
}

`\color{blue}{team} \color{black}{manh} \color{blue}{đô} \color{black}{ng}`

#include<bits/stdc++.h>
#define ll long long
using namespace std;

int main(){
    double a,b,c,s;
    cin>>a>>b>>c;
    s=(sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a)))/4;
    cout<<"Dien tich tam giac: "<<fixed<<setprecision(2)<<s;
    //meothinhle
    return 0;
}