= & 2 ) == 



vocetur arcus AYzzf + v et arcus B Y zzz c — v , hocque 

 enim modo fiimma arcuum A Y + B Y zz 2 ; aequetur lon- 

 gitudini fili, vti requiritur. 



§. 4. His ftabilitis confideremus bina triangula fphae- 

 rica rectangula AXY et BXY, ex quibus habebimus 



cof. A Y zzz cof. A X . cof. X Y, 



cof. B Y zzz cof. B X . cof. X Y, 

 fiue adhibitis dcnominationibus modo ftabilitis : 



cof. ( c -+ v) zzz cof. (a -+ x) cof. y ; 



cof. (c — v) zzz cof. (a — x) cof.y ; 

 fiue euoluendo: 



cof.f cof.i? — fin.f fin.vzzzcof.^cof.ff cof.x — cof.yfm.afm.x ; 



cof.c cof.i; -+- fm.c fm.v zzz cof.j coC.a cof.x ■+■ cof^ fm.a fm.x ,. 

 Harum aequationum fumma praebet 



cof. c cof. v zzz cof.7 cof. a cof. x; 

 differentia vero dat 



fin. c fin. v zzz cof.y fin. a fin. a*, 

 ex quibus aequationem pro curua confici oportet. 



§. 5. MuMplicetur prior harum aequationum per fin.r, 

 altera vero per cof. f , vnde orientur fequentes aequationes: 



fin. c cof. c cof. v :zz fin. ^ cof. a cof. x cof.y ; 



fin. c cof. c cof. v zzz cof. ^ fin. fin. jc cof.j'. 

 Sumatur fumma quadratorum , quo quantitas v eliminetur , 

 eritque 



fin. f cof.c~ zz: cof.y 2 (fiu.f 2 cof.tf 2 cof.x* -+- cof.c* fin.a 2 fin. x'\ 



quae aequatio ob fin. x* zzz 1 — cof. x z ; fin. a z zzz 1 — cof. a* 



et 



