We have a programming challenge to find an Area and Circumference of a Circle, so before going to write a solution in C, we need to know some facts about the circle, Ie. Area of a circle, Radius of Circle, Diameter of Circle, and Circumference of Circle. We will discuss each point step by step with the help of pictures.

What we are going to learn in this article, below is a list.

**Area and Circumference of a Circle- Table of Content**

- What is Circle
- Radius of Circle
- Diameter of Circle
- Area of a Circle, and
- Circumference of Circle
- Explanation of the Problem
- Programming Code in C Language
- The Output of the C Program
- What is Circle

**What is Circle**

A circle is a rounded closed shape, with no corner, and no edges. Where all the points in plan are at the same distance from its centre.

**How to Draw a Circle**

**Radius of Circle**

Radius is the distance from the centre of the **circle** to any point on its circumference.

**Diameter of Circle**

Diameter is nothing but the biggest line in Circle. It’s very easy to calculate the diameter of a circle, just double the radius of the circle. We can find a radius of a circle by given formula.

**Formula:** *Diameter = 2 * Radius.*

**Area of a Circle**

The area is a space covered by a circle, Circle area is dependent on its radius. We can calculate the area of the circle by given formula.

#### Formula to Find Area of a Circle

**Area of a Circle **= *πr2 or PI * Radius * Radius.*

Here PI value is fixed which is **22/7** or **3.1415926535**, but for this problem, we are using a PI value up to **5** decimal digits, If you want to know more about PI click here. You can find the PI value up to **1,00,000** Decimal Digits.

**Circumference of Circle**

The **circumference** is a Latin word which means in English “**Carrying Around**” on in Hindi “**परिधि**“. The circumference is a fixed or linear distance around it. In other words, we can say that the length of the **circle** if it were opened up and straightened out to a line segment. Below GIF clear your all doubts.

#### Formula to Find Circumference of a Circle

**Circumference of Circle **= 2*πr* or 2 * PI * Radius

**Explanation of the Problem**

Now we have both formulas(Area and Circumference), We just need to put the **R** or **Radius** value in the both given Formula.

Example 1: Radius of a Circle

Suppose the value of the Radius is 10.5, now put the same value in the formula. We already know the PI value which is **3.14159**

Area of Circle = *πr2 or PI * Radius * Radius*.

Area of Circle = **3.14159** * 10.5 *10.5 = **346.360291**

**Circumference of Circle **= 2*πr* or 2 * PI * Radius

**Circumference of Circle **= 2 * **3.14159** * 10.5 = **65.973389**

So here is a Final answers we got Area of Circle is = **346.360291** and **Circumference** is = **65.973389**.

**C Program to Find Area and Circumference of a Circle**

#include<stdio.h> int main() { /* "Area and Circumference of a Circle is C". This Programming Solution is belong to Simple Categories in C Language. -by Tutorials BookMaarks. Visit Here: https://tutorialsbookmarks.com/c-programming-questions-answers-pdf-download/ */ float radius, area_of_circle, circumference_of_circle; float PI = 3.14159; printf("Enter the Radius of Circle: "); scanf("%f", & radius); area_of_circle = PI * radius * radius; printf("\n\nArea of Circle is = %f ", area_of_circle); circumference_of_circle = 2 * PI * radius; printf("\n\nCircumference of Circle is = %f \n", circumference_of_circle); return (0); }

### Output

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