•^S^ ) 83 ( ^- 

 prolnde erit 



fi n. E G fin. A E 



fin. i D C cof. E F ~ fin. I A B cof. E H ' 

 ideoque 



fin.^BC:fin.|AD = fIn.^ABfin.|BD4-fin.iAGfin.iDC: 



fin.^ AB fin.^ AC -f- fin.i BD fin.^ DC , 

 vnde ob 



fin.i BC . fin. I AD — fm.l AB fin.i DC + fin. i AC fin. l BD, 



per Theorema praecedens , pro fin. i B C^ obtinetur valor 

 Theoremate noftro expreffus. 



§. 31. Si breuitatis gratia exprimantur arcus AB, 

 BD, DC, AC, AD, BC refpediue per litteras fl, ^, 

 Cy </, e, ff fiet 



fj ip— (fin.igfi"»^<^+fi"-'^fin-;^)(fi n.-^gfi n.-;^+fin.^^fi n.f<f) 



fin. -, a ^n. \ d ~\- fin. ^ ^ fin. ; ^r ' 



cor.^/'ri-fin.i/'r4(fin.^afin.^</+fin.-'^fin.|<:~fin.iflTin.^^fin.*tf 

 -fin.^^Tin.iafin.^</-fin.^<:Tin.iafin.^^-fin.f</Tin.i^fin.f<:) 



:^4^(fin.iafin.i^(i-fin.i^'-fin.i(;')+fin.i^fin.i<:(i-fin.ia*-fin.i</'), 



vbi 



Q — fin. i fl fin. i </ 4- fin, i b fin. i c. 



Atqui cft 



a. 3 



= cof. i(b-\-e) cof. 5 C^ - 0» 



