These are the different ways to calculate the area and circumference of the circle in C programming. #include<stdio.h>#include<conio.h>#define pi 3.14void main(){ int r; float a, c; printf(“ntenter value of radius=”); scanf(“%d”,&r); a= pi*r*r; c=2*pi*r; printf(“tArea = %.2fn”,a); printf(“tCircumference = %.2fn”,c); getch();} Output  You can also perform this calculate by defining pi as float value.    […]