# Python Program to Find Area of Circle

In this post, we will learn how to find the area of a circle using the Python Programming language.

As we know, the area of a circle is πr2, where r is the radius of the circle and π = 22/7 or 3.14

Since π is a constant, we need to take only the radius value as input.

We can import the value of π using a math module or assign the value of π to a separate constant variable.

This tutorial takes the radius of the circle from the user and calculates the area of the circle using the following approaches:

1. Using Constant π
2. Using math Module

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

Contents

## Python Program to Find Area of Circle Using Constant π

```# Python Program to Find Area of Circle Using Constant π

PI = 3.14
r = float(input("Enter the radius of the circle: "))
area = PI * r * r

print("Area of the circle = %.2f" %area)

```

Output

``````Enter the radius of the circle: 14
Area of the circle = 615.44
``````

## How Does This Program Work?

1. In this program, we store the value of π in the PI named constant variable.
2. Now, the user is asked to enter the radius of the circle. It is stored in the r named variable.
3. The area of the circle is calculated using the formula πr2. The area of the circle is stored in the area named variable.
4. The calculated area of the circle is printed up to 2 decimal places with the help of %.2f format specifier.

## Python Program to Find Area of Circle Using math Module

In the above program, we have stored the value of π in a separate variable. To get more precise and accurate results, we will use the math module.

Python has a built-in module called math that provides access to different mathematical constants and functions. It also contains the value of π.

```# Python Program to Find Area of Circle Using math Module
import math

r = float(input("Enter the radius of a circle: "))
area = math.pi * r * r

print("Area of the circle = %.2f" %area)
```

Output

``````Enter the radius of a circle: 7
Area of the circle = 153.94
``````

To use the value of π, use math.pi in the program.

## Summary

After going through this post, I hope you understand how to find the area of a circle using the Python Programming language.