Thread: area of a circle

Code:

/* Program 3: Write a program that reads in the radius of a circle and prints
			  the circle's diamater, circumference, and area. Use the constant
			  value 3.1459 fo pie. Do thes calculations in output statements.
*/

#include<stdio.h>
#include<math.h> // math library
#define PI 3.1416
int main(void)
{
	float radius, diamater, circumference, area;
	
	printf("Please enter the radius of your circle: ");
	scanf("%f",&radius); //stores variable
	
	diamater = radius*2;  // calculates radius
	circumference = PI*diamater; // calculates circumference
	area= (PI)*radius*(exp(2)); // to calculate exponent
	
	printf("Diameter: %0.2f\n", diamater);
	printf("Circumference: %0.2f\n", circumference);
	printf("Circle Area: %0.2f\n", area);

	return 0;
}

I have problem with the math function. I want to have this for the formula area= PI*radius^2, so i decided to use the math.h with the exp function but something is wrong. Can some one help me, thanks for your help

thanks SirNOt for helping me out.