Since the resultant force is exactly the sum of the two component forces, the angle between the forces (i.e. if they were placed tail to tail) is 0. In other words, the two component forces are acting in exactly the same direction. If the angle was 180, the forces would be acting in opposite directions (the resultant force would be the difference between them, not the sum), and if the angle was anything in between 0 and 180, the resultant force would be less than 5F.
