C Program for RADIUS OF CIRCLE
#define PI 3.14159
main()
{
float r,a;
clrscr();
printf("ENTER THE RADIUS OF A CIRCLE: ");
scanf("%f",&r);
a=PI*r*r;
printf("\NTHE AREA OF A CIRCLE IS %f",a);
getch();
}
OUTPUT :
ENTER THE RADIUS OF A CIRCLE: 5
THE AREA OF A CIRCLE IS 78.539743