# How to find area and circumference of circle using C Programming

C Programming

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#### C Program to find area and circumference of circle

``````
#include <stdio.h>

int main() {

float PI = 3.14, area, ci;

printf("\nArea of circle : %f ", area);

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

return (0);
}
``````

#### Output :

``````
Enter radius of a circle : 1
Area of circle : 3.14
Circumference : 6.28
``````

#### Explanation of Program :

In this program we have to calculate the area and circumference of the circle. We have following 2 formulas for finding circumference and area of circle.

``````
Area of Circle = PI * R * R
``````

And

``````
Circumference of Circle = 2 * PI * R
``````

In the above program we have declared the floating point variable PI whose value is defaulted to 3.14.We are accepting the radius from user.

``````