/* File: sinelaw.c 
   Calculate side c based on the sine law,
   given side a and two angles alpha and gamma */
#include <stdio.h> 
#include <math.h>  /* for macro M_PI and function sin() 
                      in the C standard math lib */

int main() {
    /* declare variables for sides and angles of a triangle */
    double a, c, alpha, gamma;

    a = 10.0;              /* side a */
    alpha = 90.0*M_PI/180; /* change 90 degrees into radian */
    gamma = 60.0*M_PI/180; /* change 60 degrees into radian */

    /* compute side c based on sine law and display the result */
    c = a*sin(gamma)/sin(alpha); 
    printf("c = %f\n", c);
    return 0;
}