**Understanding the problem**

We have to write a program that accepts three sides of a triangle from the user and prints its area. To calculate the area of a triangle from the three given sides, we use **Heron’s Formula**:

**Area = √ s*(s-a)*(s-b)*(s-c), **

where s = (a+b+c)/2

**Algorithm**

- Take input of the three sides of the triangle from the user and store them in the variables
*a*,*b*and*c*. - Now declare a variable of float type and calculate and store the half perimeter in it. (don’t forget to use explicit typecasting since ‘
*s*’ is of float type and*a*,*b*,*c*are*int*) - Declare a variable
*area*of*float*type and calculate and store area of the triangle in it using*s*and the given formula. - Print area.

**Code:**

```
#include <iostream>
#include<cmath> //to use sqrt function
using namespace std;
int main()
{
int a,b,c; //taking input of the three sides from the user
cout << "Enter the three sides of the triangle\n";
cin>>a>>b>>c;
float s=(float)(a+b+c)/2; //calculating s
float area=sqrt(s*(s-a)*(s-b)*(s-c)); //calculating area
cout<<"Area="<<area; //printing the area
return 0;
}
```

**Output:**

```
Enter the three sides of the triangle:
5 10 12
Area = 24.5446
```

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