C Program to calculate Area of an Equilateral triangle

In this tutorial, you will learn how to write a C program to calculate area of an equilateral triangle. A triangle is called equilateral triangle if all three of its sides are equal.

Formula to calculate area of an equilateral triangle:

Area = (sqrt(3)/4 )* (side * side)

C Program to calculate Area of an Equilateral triangle

The explanation of the program is available at the end of this program.

#include <stdio.h>
#include <math.h>

int main() {
    float side, area;

    // Prompt user for the side length
    printf("Enter the side length of the equilateral triangle: ");
    scanf("%f", &side);

    // Calculate the area of equilateral triangle
    area = (sqrt(3) / 4) * (side * side);

    // print the area value after calculation
    printf("Area of the equilateral triangle: %.2f\n", area);

    return 0;
}

Output:

Output 1:

Enter the side length of the equilateral triangle: 5
Area of the equilateral triangle: 10.83

Output 2:

Enter the side length of the equilateral triangle: 25
Area of the equilateral triangle: 270.51

Explanation:

1. Include Standard Libraries:
   • #include <stdio.h> for standard input and output functions such as printf and scanf.
   • #include <math.h> The sqrt function which we have used in the program is present in this library.
2. Declare Variables:
   • float side, area; The side variable is to hold the value of side of the equilateral triangle and area variable is to hold the area value after calculation.
3. User Input:
   • printf("Enter the side length of the equilateral triangle: "); prompts the user to enter the length of side of triangle.
   • scanf("%f", &side); reads the value entered by user and store it into the side variable.
4. Calculate Area:
   • area = (sqrt(3) / 4) * (side * side); This formula is used for calculating the area.
5. Print Result:
   • printf("Area of the equilateral triangle: %.2f\n", area); prints the area of equilateral triangle with two decimal places.
6. Return Statement:
   • return 0; indicates that the program executed successfully.