The topic of this work is thr three-hinged girders. Three-hinged girders are supports that consist of two discs that are connected to each other by a joint, while each is hinged to the base. At the beginning of the work, three jointed supports, their characteristics and types, and the basic laws of mechanics that the sistem must satisfy are defined. Below are shown the methods of joining this type of three-hinged girders. Three-hinged girders have a very wide application in construction, and their examples are given in the chapter on applications of three-hinged girders. The solution methods and equilibrium conditions that must be met by a statically determined system when calculating reactions using analytical ang graphical procedures are further explained, In the paper, 6 numerical examples were solved, where the procedure for determining reactions and internal forces using analytical and graphical methods was presented, and the obtained results were compared.