Python Program To find Area Of Circle

Write a python program to find area of circle using radius, circumstance and diameter. The Python area of a circle is number of square units inside the circle. Standard formula to calculate the area of a circle is: A=πr².

Python Program to find Area Of Circle using Radius

If we know the radius then we can calculate the area of a circle using formula: A=πr² (Here A is the area of the circle and r is radius). In this python program, we will find area of a circle using radius.

# Python Program to find Area Of Circle using Radius

PI = 3.14
radius = float(input(' Please Enter the radius of a circle: '))
area = PI * radius * radius
circumference = 2 * PI * radius

print(" Area Of a Circle = %.2f" %area)
print(" Circumference Of a Circle = %.2f" %circumference)

We defined pi as global variable and assigned value as 3.14. This python program allows user to enter the value of a radius. And then, it will calculate the area of circle as per the formula. The output of Python area fo a circle is

 Please Enter the radius of a circle: 6
 Area Of a Circle = 113.04
 Circumference Of a Circle = 37.68

Python Program to find Area Of Circle using Circumference

Distance around the circle is called as circumference. If you know the circumference then we can calculate the area of a circle using formula: A= C²⁄ 4π (Here C is circumference)

# Python Program to find Area Of Circle using Circumference

import math

circumference = float(input(' Please Enter the Circumference of a circle: '))
area = (circumference * circumference)/(4 * math.pi)

print(" Area Of a Circle = %.2f" %area)

Python area of a circle using circumference output

 Please Enter the Circumference of a circle: 26
 Area Of a Circle = 53.79

First, We imported the math library and this supports us to use all the mathematical functions in Python programming. In this Python example we can call the PI value using math.pi

import math

Next line of python program allows user to enter the value of a circumference.

circumference = float(input(' Please Enter the Circumference of a circle: '))

Using the circumference, this program will calculate the area of circle as per the formula: A= C²⁄ 4π

Python Program to Calculate Area Of a Circle using Diameter

Distance across the circle passing through the center is called as diameter. If we know the diameter then we can calculate the area of a circle using formula: A=π/4*D² (D is the diameter)

# Python Program to find Area Of Circle using Diameter

import math

diameter = float(input(' Please Enter the Diameter of a circle: '))
area1 = (math.pi/4) * (diameter * diameter)
# diameter = 2 * radius
# radius = diameter/2
radius = diameter / 2
area2 = math.pi * radius * radius

print(" Area of Circle using direct formula = %.2f" %area1);
print(" Area of Circle Using Method 2 = %.2f" %area2)

This area of a circle program allows user to enter the diameter value. Next, it will calculate the area of circle as per the formula we shown above.

We also mentioned other approach.

diameter = 2 * radius

radius = diameter/2

area = π * radius * radius