In geometry, the perimeter of a circle refers to the total length of the boundary of the circle. It’s an important metric when dealing with circles in various mathematical and real-world applications.

In this article, I will explain you two different methods to find the perimeter of a circle using Python. We are going to use the mathematical constant π (pi) which is approximately equal to 3.14159.

Let’s see how to implement these methods step-by-step in python!

The below code defines a function circle_perimeter which takes the radius of the circle as input and returns its perimeter. You can then call this function with the desired radius value to get the perimeter of the circle.

import math

def circle_perimeter(radius):
    perimeter = 2 * math.pi * radius
    return perimeter

The following using the example usage:

# Example
radius = float(input("Enter the radius of the circle: "))
perimeter = circle_perimeter(radius)
print("Perimeter of the circle:", perimeter)

Let’s see another method, we directly calculate the diameter of the circle (which is twice the radius) and then multiply it by an approximation of pi (3.14159) to find the perimeter.

def circle_perimeter(radius):
    perimeter = 0
    diameter = 2 * radius
    perimeter = diameter * 3.14159  # Approximation of pi
    return perimeter

The following shows how to use the above function:

# Example usage
radius = float(input("Enter the radius of the circle: "))
perimeter = circle_perimeter(radius)
print("Perimeter of the circle:", perimeter)

Calculating perimeter of a circle is really simple, if you just follow the above code snippets.