Calculate Area and Circumference of a circle using C

#include<stdio.h>
main()
{
int rad;
float PI=3.14,area,ci;

printf("\nEnter radius of circle: ");
scanf("%d",&rad);

area = PI * rad * rad;
printf("\nArea of circle : %f ",area);

ci = 2 * PI * rad;
printf("\nCircumference : %f \n",ci);
}