rOLYGOXORVM RECTIL.NRORVM. 9» 



apta , fequens t.imea transformatio qiioquc adhibcri 

 poterit , quaerjtur 



ri<i R / f _i_ c An. ( B _f- C ) \ 

 e_ _ i/Yn.B-Hcflt.f B - t- C ) _ U^^- ^ V ' H 6/ , ,:.^- ^ 



a 6j»:.C-Haji/i.;B^C) ^ p . , .ijin.^ n -^ c ) \ 



iin. V- (, I ^i ^-^,^ -g — ; 

 eritque 



-ffin.(B-f-C) __ -^fi n (B-hC)' 

 ""S- — rt_t-^col.(B-i-C;- iH-l-cou(B+C)* 

 Ex hac autem poftrema formula, pofito -— tang. F» 

 facile deducitur 



tang.(KB-+-C) + A) = -tang.l(B + C)tatig.(4.5VF). 

 Pro hoc problcmate dc valore anguli A , nulJa re Tab. I. 

 manet ambigiiitas , ceu ex ipfa contemplatione figu- ^'S- *• 

 lae appnrer. Nam datis angulis externis ^BC, 

 rCD et Literibus AB, BC, CD , anguius «AB 

 perfede detcrminatur 



9. Problema 8. Datis lateribus a , b , c ^; 

 anguUs A , C inuenire anguiwn B. 



Aequatio tertia cuoluta dat 



flrin.A+fin.(A+B)(^-t-fcor.C) + <;cor.(A+B)fin.Cz:o. 

 Quod '^i igitur ponatur tang. E — ~]^^^ , fiet 



tffin. ^^'-^(^^''(fin.CA + B^cof.E+cof.^AiBTiD.E^-o vcl 



flfin.A-+'j;j^fin.(A-}-B-hE')=:o, liiiicque Fig. 0. 

 fi n. ( A H- B -i- E ) =r - ±ii^V- il?LL . 



Quod fi quadriliitcri A B C D dingonalis B D co ici- 

 piaiur du(fla , fiet tang. CBDrz ^-^^- , ideoque E 



indij,it-ibit angulum CBD, hinc autem coududetur efle 



iVl 2 AH-B 



