Howdy readers, today you will learn **how to write a c program to find the circumference of a circle**.

The **circumference** of a circle is the measure of the boundary of a circle.

The circumference of the circle is calculated using the **circumference formula** that needs the value of the **radius** of the circle and the value of **PI** which is a mathematical constant such that **π = 22/7** or **3.14** (approx).

**Circumference of Circle = 2πr**

Where,

- r is the radius of the circle
- Π = 3.14

This program takes the radius of the circle from the user and then calculates the circumference of the circle using the circumference formula.

So, without further ado, let’s begin this tutorial.

**C Program to Find Circumference of Circle**

**C Program**

// C Program to Find Circumference of Circle #include <stdio.h> int main(){ float radius; float CI, PI = 3.14; // Taking Input printf("Enter the radius of the circle: "); scanf("%f", &radius); // Calculating Circumference CI = 2 * PI * radius; // Display Circumference of Circle printf("Circumference of the circle is: %.2f", CI); return 0; }

**Output**

Enter the radius of the circle: 7.2 Circumference of the circle is: 45.22

**Explanation**

float radius; float CI, PI = 3.14;

We have declared three float data type variables named **radius** **CI** and **PI**. The **PI** variable has been assigned a value of **3.14**.

printf("Enter the radius of the circle: "); scanf("%f", &radius);

Now, this program asks for input. The value of the radius entered by the user is taken using the **scanf()** function. The value gets stored in the **radius** variable.

CI = 2 * PI * radius;

The circumference of the circle is computed with the help of circumference formula, circumference = 2πr.

In this program, we are using **PI** in place of **π**. So, our formula looks something like this:

**Circumference = 2 x PI x radius**

The circumference obtained gets stored in the **CI** variable.

printf("Circumference of the circle is: %.2f", CI);

After that, the circumference of the circle is displayed as output using the **printf()** function.

**Conclusion**

Today you learned **how to write a C program to find the circumference of a circle**.

Besides that, you have also learned about the circumference of a circle and the mathematical formula to calculate the circumference of a circle.

If you have any questions or issues regarding the program, comment down your queries in the comment section.

Thanks for reading.

Happy Coding!!

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