f^ J f\ 



I +cof A C — n--(i-f. cofBC), h. e. 

 cof|AC = ;icof^BC< 



Cum itaque cuicuiique arcus Cf) valoii iidem refpondeant 

 valoies D C'— DC, puncla C eandem curvatn defcribent 

 ac punfla C, verum in heniifphaerio ojjpofito ADZO, 

 circulum nempe niinorem , cuius a centro diftantia ~ 

 "' ~ ^ , pofito radio fphacrac — i (f. ip.}. 



§. 21. Sit A E C F circulus fphaerac maximus per pig. 9. 

 punna'A,B,E, P' tranfiens, quae cum punflis A,B,E,K, 

 problematis III conveniunt, litque P medium arcus A B-cj, 

 G medium arcus E F, et polus circuli' minoris ECF pro- 

 blemati III fatisfi^icientis; defcribatur denique e polo P per 

 punfla A, B, ciiculus miiior ACB, qui priorcm in C ad 

 angulum leQum fecabit. Duflis nempe arcubus circulorum 

 maximorum PC, GC, erit in triangulo fphaerico P C G, 



cof P C G — ' ^''~'' L^£Ji'SS\. 



jin. 1' V Jm C G 



Eft autcm P C = P A = f a,. ' 



tangCGrtangEG-tangiEFri^^^- CJ- ^l-), 

 et P G — E G -I- P E; unde fit 



cof P C G = c-of P E - f iii P E ta ng E G — cof | a 



CI'iare cum fit 



/jri 1« tang EG- 



/7 fii:i ;-. X 



tang|AE— — '.Jll {%, i-,^ idcoque 



ncofi a-l- I 



fm 



