C# Program to calculate area of pentagon

Program

using System;
namespace area_of_pentagon
{
	class AreaOfPentagon
	{
		static void Main(String[] args)
		{
			int apothem, side;
			float area, area_num;
			Console.Write("Enter the apothem:\t");
			apothem = int.Parse(Console.ReadLine());
			Console.Write("Enter the length of side:\t");
			side = int.Parse(Console.ReadLine());
			area_num = (5 * side * apothem);
			area = area_num / 2;
			Console.WriteLine("Area of pentagon: " + area);
		}
	}
}

This C# program calculates the area of a pentagon using the apothem and side length provided by the user.

1. using System;

   • Imports the System namespace, allowing the use of built-in functions like Console.WriteLine().

2. namespace area_of_pentagon

   • Defines a namespace named area_of_pentagon to organize the class.

3. class AreaOfPentagon

   • Declares a class named AreaOfPentagon, which contains the program logic.

4. static void Main(String[] args)

   • The Main method serves as the entry point of the program.

5. Declaring Variables:

   • int apothem, side; → Stores the apothem and side length of the pentagon.
   • float area, area_num; → Stores intermediate and final results.

6. Reading User Input:

   • Console.Write("Enter the apothem:\t");

     • Displays a prompt to enter the apothem.

   • apothem = int.Parse(Console.ReadLine());

     • Reads user input as a string, converts it to an integer, and stores it in apothem.

   • Similarly, the side length is read and stored in side.

7. Calculating the Area:

   • Formula: Area of a pentagon = (5 × side × apothem) / 2
   • area_num = (5 * side * apothem);
     • Computes the numerator (5 × side × apothem).
   • area = area_num / 2;
     • Divides by 2 to get the final area.

8. Displaying the Result:

   • Console.WriteLine("Area of pentagon: " + area);
     • Prints the calculated area.

Key Points:

• The apothem is the perpendicular distance from the center to a side.
• The side length is the length of one side of the pentagon.
• This formula applies only to regular pentagons (all sides and angles are equal).
• The program assumes that input values are always valid (i.e., positive numbers).

Output

$ mcs AreaOfPentagon.cs
$ mono AreaOfPentagon.exe
Enter the apothem:	7
Enter the length of side:	15
Area of pentagon: 262.5