POLYGONOPvVM RECTILINEOaVM. 105 



^^•^^'^— CflT^)y H-}col.i b.coi. s D-(tf-z>jc/-f; iia.iii.liu. i D 



qii.ie formiil.i omnino cum fuperioii congruit , tum- 

 que tt hoc modo cxprimi poteit : 



Tang. ,{.. L, _ ^^_^^ , ^^^_^^^ __ , ^_ ^^ ^^_^.^ .^ ^^^^^ . ^^ j—jT^ • 

 Porro quiim fit 



Tang. ;(A - C+ B - D) _ 7+ 7,^(1:^qT^„7.-. ^ j:rB) 



fiet hinc 



Tang.KA-C + B-D)_ ^^.^-jI^^^.I^jI^r^^^DZ^^q:^- 



Cacterum inuento anguio D, faciiii.nc iaucaietur A 

 ope (orauilac 



a fin. B + .^Tin. ( A 4- B) + i' fin. ( A -4- B -f- D) — o. 



19. Probltma V. D^;/j lateribuf n, b, c ^; <7«*. 



B, D iuuenire reliquos angu/os A, C -?; /^i/wi d. 



Qiiiicratur primum angulus A ope formulae ex 

 aequ:U:one qiiarta deduccndae 



fln. A :^ -4- i' cof. Bj 4- ^ cof. A fin. B — ^- fin. D, 

 ponenco nimirum 



Tnng.E — -i^"--t„fietquc fin.(A-^E)r:'-4v^'^ , 



tum \cro fponte innotcfcit angulus 



C = 360" - (A -+- B -H D). 

 Latus antcm d habtbitur per formulam 



J . « Jin. C — a iin. B 



/"-..(A-hB) 



Tom, XX. Isou.Comm. O Cacte- 



