Ex quo rrianifello ddducitur 



cof Zb: cof, C i- — coi: A </ zr co£ B r. cof. C k 

 Sinvifi nuf-or.c qacrque olbaditur cOk; , 

 - cot^ A a roi. C f — cof. B b — col. A r cof, Q a, 

 DeiiiLic pro quadrihtcro AC c b^ habemus pcr Lem- 

 ma noiiiiim III : 



coC Ab=^ fin. A C c: fin. ^t' C -- cof. C^-. cor A C r. cof b c C 

 et pro quadrilatero c C f B, vi eiusdcm Lemmatis: 

 eol. Ki7— fjn. BCV. fin. flt C — cof.Cf.corBCr.cor.^rfC. 



Qiiuni nunc fit BCf — ACf — 90°^ acQ—bcQ—c^o^r 



obtiucbimus y 



cof. B^n^cof. AC<:. cof. iuC -cof.Cf. fiii. ACc. fin.^fC, 



hincqne 



col. A b. cof. C t' + cof. B ^ = C r'- cof Cf') cof. ACc-.cof.kC 



— fin.C(r\cof.ACr.coI bcQ^ 



liue ob- 



cof A ^ ~ fin. C c. cof ACf et cof.Ci?— fin.Cc. cofZ^tC, 

 cof. A b col. Qc -h cof, B a rr cof. A c. cof. C b^ 



Simili ratione dimonftrajitur cffe : 



cof. A b; cof B f — cof. B b. cof. A r -f- cof C a , 



mnhiplicaia it^itur priori aequations pcr cof. B « ct 

 porteriori pcrcol', Ca, addiiisque producftis , coule- 

 quemur : 



1. coC A f.cof Ci^.cof Ba-— cof A^.cof B^.cof CtM cofBa'' 



2. cof. A^. cof Br.cof.CG— cof AccofC^.cofBij-KofCrt', hinc 



3 . cof. A b' cof B f. coC C a + cof. A c cof. C Z^. c of. B a — 



of. 



