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.

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.