loo DE RESOLVTIONE 



Si in hiic formula poniuur b zz o , quo cafu Tetra* 

 fgcnum iii trianguUim abic , fict 



Tans.i(A-D)-;^^;Tang4(E+C]=^^°Tang.i':A+D), 



quae eft iam diu cognita trian'a,uli prcprietas. Simi- 

 1i modo fi ponatur B — o , fiet 



Tans;. i (A - D) zr ^^1=^ Tang. ', C 

 itcrum pro triangulo. Prattcr has formulas inucfti- 

 gandae A — D infcruientcs , etiam (equentcs notari 

 niercntur : 



fin ^'A —]')') — (a-— c ») iin.(E-j- C,'— 67.>i.[B-C)-f-'-Q3i"m.C~;i'c/fn.B „-,1 

 "'•^ ~ * ^* — o'-4-i'-f-:--t-:n6co.E-+-:nccoJ"(BH-C;-J-:deC3/.C 



Tan? (A - D) — (a' — c')r/n.(B-t-C:— iVm.(B --C?-H'-fl6jm.C — 2hcjm.i 

 ^* ^ '' (9^^c"-) c3j.(B'-f-C;-H-6-coj.(B-C)-H-'!C-(-:aico/.C-t-jf':co/".B 



quae formulae inde dcducu.itur , qucd fit 

 Tans. A — — (^'/'''•'B-t-cJ"'-(B-4-ci _j. 



^* a H- i wj- B -(- c coj. (B -j- C) 



Tanp- 7) — — J,^/^"' c -K_a/m (b ->- C)) _ 



^* -^ — c -i-bcoj. C -+- c co/. (B -+. C) • 



Si in formula pro fui. (A — D) , ponatur h — o 

 quo cafu Tetragonum in trianguhim nbit , fict 



<\n /" A _ n^ — t"^ — *=')■/'«• '3 -+- C) — (c' — <>';/z>!.;a-4- D) 



iiu. ^A iv; — 5i-_f.c^.t.7icco/.:B..+-C) — a^ 



quae eft cgregia trianguU proprietas , haud vulgo 

 cognita. Inucntis per formulas pracfcriptas omnibus 

 anguhs quadrilateri , latus d per acquationcm quar- 

 tam qr.aeri pollct , praellabit tamcn formularum 

 heic allatarum vfum adhibere. Scilicct cx §. z, 

 dcducitur 



dd - {a fin. B - c fin. Qf -\-(b~\-a cof. B 4- ^ cof. C)' ; 

 inucnto igitur 



Tang. ; (A - D + B - C) = ^^^ , Set 



