POLYG0NO.1VM RECTILINEORVM. 87 



ert enim 



tang.KC4-F)=r-ta:ig(i8D°-'[C-|-F3}--tang.KC'-f-Fy, 



idcoquc 



3<jo° _- ( C -f- F ) — -f- C -f- F , fiue 

 C'rr36o°-C-2F. 



Ratio iiiuem lniius ainbigiiitatis efl: manifLrta , dum 

 connderamus luper dingonali AC conftrui pjflc tri- 

 angulum A D'C ipli ADC fimilc ct aequale, tum 

 autcm fitt 



ang. h'Cc— 360' -DCtr-2BCA, 

 cft enim 



-: ( D C t' -f i:' C c ) = A C r = 1 80 - B C A. 



6. Problema 5. Datis latcribus a , b , c et 

 anguHs B , D inueuire latus d. 



Pro hnc probkmate inferuit aequatio fecunda , 

 per quam fit : 



dd-\- 2 c dco^L.T) -\- c c~a a -\- ^abzol^-\- b b 



hincque 



dd-\-iicdco{.'D-\-ccco^\y-aa-\-iabco^.'K'\' bb-cc^n.Tf^ 

 in Jocum autem ipfiu» 



a a -{- "2. a b coi^Q-^- b b ^ fubflituatur" 



[a-\-b)^ — ^ab fin. \ B' , ita vt fit 



(^-f-<7cof.D)'rz(fl4-^;;-6'ffin.D'-4fl^fin.iB', 

 hincque fiet : 



d^ccoa:-=.-V{a^b-\ c^xn,Y))[a^b-c^m.T))v( —^-^-^^ --\ 



' \^^x\-b^ci\\\A)){a-\-b-Qi\^.\:^)J 



pofito 



