The two component forces F1 and F2 acting on the pin in Fig. 2-7a can be added together to form the resultant force FR = F1 + F2,as shown in Fig. 2-7b. From this construction. or using the triangle rule. Fig. 2-7c. we can apply the law of cosines or the law of sines to the triangle in order to obtain the magnitude of the resultant force and its direction.