PROBLEMATIS ANALYTiCI. 15^ 



Qnum igitur (Tt 



fin, A E cof. E A D= cof. E B 

 fin.AFcor.FAD=eor.FD 

 fin.AEfin.EAD = {Ln.EMrrcoCBE 

 fin. AF fin,FAD=ifin.FN — -co1:BF 



prodibit vt antea . 



cof.EF=:coCAEcor.AF + coCBEcoCBF + cof.DEcof:DF. 



Lemma IIL 



4. Si ex puna:o quocanque A in fuperficie Tab. L 

 Sphaeriea , ducantur ad tria punda B, C, D in eo- ^^S^ 3« 

 dem circulo maximo lita , arcus circulorum maxi- 

 morum A B, A C, A D , erit 



coCACfin.BD=:cof,AD(in.BC-i-cof.ABfin.CD^ 

 tum vero) 



finj^Cfiii.EDcoCACB-coCABcof.CD-coCADcof.BC- 



Demonftratio. 



Quum. fit 



coCABi^coCACcoCBC+fia.ACfin.BCcof^ACB 



atque 



coCAD:=:cof.ACcoCDC-fin.ACfia.CDcoCACB 



habebitur 



coCABfm.CDJrcoCADfin.BC=cQCAC(poCBCfiu.CD4fcoCCDfin^C) 

 =;co£ACfin. BD.. 



EH 



