-^.^ ) 8S ( ^c*- 



f. 4. Hoc Thcorcmate iam dcmonftrnto nunc pro- 

 gr-edimiir ad Thcorcma noflrum principalc priiiium, quod 

 ita enunciatur. 



Thcorcma i, 



Si bini drcult B G D , C G A in fupeyfick Sphaerae 

 defcripti fe imcrfcccnt ad onguhim rc^utn, ct ex punclis A, B, 

 fvhi iirculus maximus per polos E , F circulorum propo/iio- 

 rum tranfiens Jecat circulum B G A , ducantur ad puncluni 

 quoduis H altcrius circuli C G D, arcus circulorum maximo- 

 rum B II, A H, erit fin. { A H -.fin. l B H in conjlanti ratione. 



Dcmonfl.ratIo. 



Pro hac propofitionc dcmonftranda, ratioclnio pri- 

 mum vtamur Analynco, qucm in fincm arcus A H, B H, 

 GF, GE, AF, BF, EF refpcdiuc indigetcntur litteris 

 jf, y, tf, bj c, e, d, anguhis autcm HFA littera Cp, tum- 

 que fict : 



cof. .V — cof. a cof. c -\- fin. a fin. c cof. Cf) ct 

 cof. j' = cof. a cof. e -\- fin. a fin. e col. Cj) , 



quum itaque fit cof. a zz J J , fi pro cof. a hic valor in- 

 troducatur, prodibit 



cof. X — '-^;- -I- fin. a fin. c cof. Cj) ct 

 cof. y — '2LI^Iil -\- fin. a fin. e cof Cp, tumque 

 fin. - v' = \^1°L^. — Mf-^-w/.dcor.c _ . f,„ ^ f,n. ^. cof. ^, 

 fm, • j--- - L^^°^.2 — cor.^-.of.dco,.^ _ ^ f,p. fl f,„. <. col. Q. 



Quum 



