Write a program that calculate circle’s area

Write a program that take radius of circle as input and then computes and displays circle’s area
Formula: Area = PI * r^2

Source Code:

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#include <stdio.h> #include <conio.h> void main (void) # define PI 3.142857 { clrscr (); float A, r; printf("Enter the value of r: "); scanf(" %f", &r); A = (PI * (r * r)); printf("\n Area of a circle = %f", A); getch(); }

Result:

Enter the value of r: 3

Area of a circle = 28.285713