FOLYGONORVM RECTILINEORVM. 119 



Liqiict Qutem hinc fiue e , feu a tt. b facile inue- 

 niri , pro iniieniendo (cilicet: e , ponatur 



.fictque 



f = (^fin.B+rfin.(B-fC) + ^nn.(B + C + D))Cofec.F. 



Tum vero habcbitur per priorem earum 



flmili ratione inuenitur by per pofteriorem. 



Si cx prima aequationc fit quaercndus angukis B,' 

 fada eiiolutionc tcrmiuorum qui hunc angulum iii- - / 

 voluunt , (latuatur 

 ri"; -^-^4" — r-T = Tang. G, tumque obfcruetur eflc 



^'+t-'+/"+2^t-cof.C + 2^^('cor.(C+-D)-+2frt'cofD 



-(^+^xor.C+rt'cor(C+D;/+;c-fin.C+^rin.(C+D)r 



= ^lIi!lL£.-±±I^^lc_,^^ , i^j„^ •^j.g^ gg^ aequatio prima 



ee — «'4-'WVV£^d//n.^CC+D)}2_^ ^, ^ ^c_f;,..C- f-d /'' "•fC-HDJ ^cof .(B+G) 



tumque 



cx qua aequatione ycI alia huic aiiuloga facile de- 

 tcrminatur angulus B. Dcterminatio autem anguli 

 C maximam facedit operam , atque ita (ufcipienda 

 vidctur; fa,fla euohuione lerminorum qui angulum C 



inuoluunt , (latuamus 



- X<1 nv T 



c -^ d coj. D 



quo 



Tuog. I =3 ^^- B_ ^ Tang.Lzz ''-'' 



