Python Program to Find Area of a Circle
Last Updated : 21 Feb, 2025
The task of calculating the Area of a Circle in Python involves taking the radius as input, applying the mathematical formula for the area of a circle and displaying the result.
Area of a circle formula:
Area = pi * r2
where
- π (pi) is a mathematical constant approximately equal to 3.14159.
- r is the radius of circle .
For example, if r = 5, the area is calculated as Area = 3.14159 × 5² = 78.53975.
Using math.pi
math module provides the constant math.pi, representing the value of π (pi) with high precision. This method is widely used in mathematical calculations and is considered a standard approach in modern Python programming. It is optimal for general-purpose applications requiring precision and speed.
Python import math r = 5 # radius area = math.pi * (r ** 2) print(area)
Explanation: area is calculated using the formula math.pi * (r ** 2), where r ** 2 squares the radius, and math.pi ensures high precision for π.
Using math.pow()
math.pow() function is optimized for power calculations, making it more readable when dealing with complex exponents. It is often preferred when working with formulas involving multiple power terms, though it is slightly less common than using ** for simple squares.
Python import math r = 5 # radius area = math.pi * math.pow(r, 2) print(area)
Explanation: math.pi * math.pow(r, 2), where math.pow(r, 2) raises the radius to the power of 2, math.pi ensures the use of a precise value of π.
Using numpy.pi
numpy library is designed for high-performance numerical computations and numpy.pi provides a precise value of π. It is especially efficient when performing bulk area calculations or working with arrays of radii, making it ideal for large-scale computations.
Python import numpy as np r = 5 # radius area = np.pi * (r ** 2) print(area)
Explanation: np.pi * (r ** 2), where np.pi provides a high-precision value of π and r ** 2 squares the radius.
Using hardcoded pi value
This is a simple and traditional approach where the value of π is manually set as a constant . It is often used in basic programs or quick prototypes where precision is not critical. While this method is easy to implement, it is less accurate and is generally not recommended for professional or scientific calculations.
Python PI = 3.142 r = 5 # radius area = PI * (r * r) print(area)
Explanation: area is then calculated using the formula PI * (r * r), where r * r squares the radius.