The Program in C++ to find the area of Scalene Triangle is given below:

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    double a, b, c, s, area;

    cout << "Enter the lengths of the three sides of the triangle: ";
    cin >> a >> b >> c;

    s = (a + b + c) / 2.0;
    area = sqrt(s * (s - a) * (s - b) * (s - c));

    cout << "Area of the triangle: " << area << endl;

    return 0;
}

Output:

Enter the lengths of the three sides of the triangle: 5
6
9
Area of the triangle: 14.1421

Pro-Tips💡

In this program, we first declare four variables: three double variables (a, b, and c) to store the lengths of the three sides of the triangle,

and a double variable area to store the area of the triangle.

The program prompts the user to enter the lengths of the three sides of the triangle using the “cout” statement, and uses the “cin” statement to input the numbers.

We use the Heron’s formula to calculate the area of the triangle.

Heron’s formula states that if a triangle has sides of length a, b, and c, and s is the semiperimeter of the triangle (half the perimeter),

then the area of the triangle is given by: Area = sqrt(s*(s-a)(s-b)(s-c)) where s = (a+b+c)/2 Finally, the program uses the “cout” statement to output the area of the triangle to the console.

It is important to note that the given sides should follow the triangle inequality theorem (a+b>c, b+c>a, c+a>b) otherwise it will result in a runtime error.