This program to find the area of the circle

Formula:

Area of a circle is pi * r * r

where r is a radius of a circle.

Note:use Math.PI constant to get value of pi

This programs gets the input as radius of the circle from the user and do the calculation and display the result

Example:

Radius of a circle is 5

Then Result=3.14 * 5 * 5

Output:Area of a circle is 78.53981633974483

#include <stdio.h> #define PI 3.14159 int main() { float sum=0; float r; printf("Enter the radius of the circle\n"); scanf("%f",&r); sum = PI*r*r; printf("The area of a circle is %f\n",sum); return 0; }

Output:

Enter radius of the circle 8

the area of a circle is 201.06192982974676