C Program to find area of Regular Polygon sides

Program

#include<stdio.h>
#include<math.h>
void main()
{
    int num, side;
    float denominator, numerator;
    float tval, area;
    printf("Enter the number of sides:\t");
    scanf("%d", &num);
    printf("Enter the length of sides:\t");
    scanf("%d", &side);
    numerator = pow(side, 2) * num;
    tval = 180/num;
    denominator = 4 * tan(tval);
    area = numerator/denominator;
    printf("Area of polygon: %f\n", area);
}

Output

Enter the number of sides:      4
Enter the length of sides:      3
Area of polygon: 5.556327