C ^5 > 



titr triafiguli proprietates valent etiam de ip- 

 fis viribus. 



In triangulo A P C eric 



AP ; PC - ftn. ACP -: fin.CkV, 

 AP : AC ^ fm, ACP : ' Ctn. APC, 

 AC : PC =y?/7. APC : 'ftn. CAP, 

 id esc li vocemus anguhim inter directiones 

 AP ec BP, «; inter AP et PC, /3; inter 

 BC et CP, y; porro vis AP = P, vis 

 B P = P' , et vis compofita C P ~ R ; quoni- 

 am L ACPSL CPB etT?/?. GAP = fin, 

 (i8o° - CAP), 



P : B = fn. y : fn. ec. , 

 P ; F z=:'fn. 7 : fin. (3, 

 P : R z=: fn..0 -, fn. «; 

 li autem P D aequalis fit P C , vidimus vires fic 

 tigentes aequilibrium fervarc; igitur, quoni- 

 am fn. DPA = fn. (i8o° - APC) =; //«./3 

 tifn. DPB = /?«. (i8o« - CPB) =-fn.y^ 

 erit P : R = fn. DPB : fn. APB, 

 P : F = /?«. DPB : fn. DPA, 

 F : R zz'fn. DPA : /?«. APB, 

 id est : tres vires in aequiUhrio ita funt dis- 

 poftae , ut fngularum magnitudines fnt inter 

 fe , uti fnus angulorum , qui intcrcepti funt 

 inter directiones reliquarum duarum viri^ 

 wn. 



, ( vir. 



