F1=12 кн F2=10кн F3=8кн a1=120 a2=55 a3=0

It looks like you are trying to analyze forces with their magnitudes (F1, F2, F3) and angles (a1, a2, a3). To better assist you, could you clarify what specific calculations or analysis you want? Are you trying to find the resultant force, or perhaps you are looking for something else such as components of each force, or equilibrium conditions?