tC D E R-ESOL V T lONE 



ex qnibus inuenitnr : 



v. 4^^(in.B y -.• 4«i-fin.iiuu.F 



^ ' Jtn.P ' ^ ' Jm. F 



Tab. I. Si duda intelligatur A C diagonal s quadrilateri 

 Fig. 4. A B C D, facile cohlKibit cffe angulu.n B C A = F, 



hincque F -i- C =:: i &o° - A C L, uieo.-ue L (K + C) 



ii: 90° — i A C D, quare 



Tang. UF+C;- cot. ^ A C D. 

 Hacc igitur folutio eo rtduciuir , vt inucfligato 

 Tang. B C A- Tang. F = , "^^"'^ , 



quaeratur Tang. -J A C D pcr fonni!l.un 



"^" C^ + W + '^^ ('■ -^ JTT^ "^^ ' 

 quo fit^o crit ang. C zz i 80° - B C A — A C D. 

 Cactcrum patct tang. I ( C -4- F ) hcic ambiguum 

 efle ipfiquc valorcm taui negatiuum , quam pohti- 

 \um tribui polTc , quapropter pro C biuos quoquc 

 habebinnus \alorcs , quorum fi vnus exprimatur ht- 

 tcra C, altcr pcr C; ncccflum cfl: vt lit 



O zz 360° - C - a F , 



cll 



