code: public static final double getAngleFromSSS(final double s0, final double s1, final double s2)
      {
          return Math.acos((((s0 * s0) + (s1 * s1)) - (s2 * s2)) / (2 * (s0 * s1)));
      }
docs: Returns the angle between s0 and s1
  http://www.mathsisfun.com/algebra/trig-solving-sss-triangles.html
  @param s0
  @param s1
  @param s2
  @return