Force analysis of triangular cantilever support

① The transmission of force can only rely on solid matter as the path; ② The transmission of force is a shortcut; (3) It is difficult to describe the stress line clearly because of the complex stress on the connecting point of the bar. The formula in the problem is the result of an idealized assumption mode, that is, assuming the structure as shown in the following figure, that is, assuming that the nodes are hinged, AB and BC are assumed to be two-force bars with only axial tension or pressure.