POLYGONORVM RECTILINEORVM. 203 



quae funt aequationcs frima et frcw.da pro refolutio- 

 ne Fentagoni. 1 leiiariam quadratorum euolutionem 

 ct reliquas redu&iones , quibus ad h:>s aequationes 

 pertingimus, heic exponere nihil attiriet , quum ha- 

 rum operationum ratio ex praecedentibus fatis in- 

 teliigatur. Keliquae tres aequationes pro refolutione 

 Pentagoni fcquentes kabentur: 



III. a fin. a + b fin. (a+{3)+^ fin. (a-+(3+Y) + </fin.(a+|3+ y4-^)~o 



IV. a fin a + £fin (a+(3) + £'fin.(a+(3+Y)--^fin.£:--o 



V. tffin.a + &fin.(a+(3) — f fin.(o" + e)--£ , fin.£ — o 

 quarum tertia eft ipia noltra aequatio primitiua (A) f 

 quarta vero et quinta ex hac deriuantur , fubftituen- 

 do primum pro fin. (a •+ (3 -4- y -h o), — fin. s tum 

 vero ttiam pro fin. (a +- (3 +- y), — fin. (£ +- e), 

 quum nempe lit 



a+P+7+^ 360*— s et a-f-p+yz=:3^o — £ — £• 

 1 2. Pro Hexagono primitiuae noftrae aequa- 

 tiones fequentes funt: 



tffin.ft+^fin.(a+p)+ffin.Ca+p+Y)+</fin.(a+(3+Y+^} 



+ < J fin.(a+(3+Y+£+e)- = - ( A ) 

 flCofa + ^cof.(a+(3)+fcof(a+(3+Y)+^cof(a+(3 + Y+^) 



+ e cof.(a+(3+ y+ £+e) =-/ (B). 



Prior vero his quoque binis modis exprimatur : 



tffin.tt+^fin.(a+p)+ffin.(a+p+Y)+^fin.(a+(3+Y+-^)=^n-^(Q 

 * fin.a+£ fin-Ca+(3>U fin.(a+(3+ Y)=^fin.(e+-£)4-£fin.£ (E). 

 Pofteriori item binae hae tribuantur formae: 

 flCofa+^cof(a+(3)+6-cof.(a+p+Y)+^cof(a+p+Y+^)--^cof^~/(D) 



tfCoCa+^coi.Ca+P)+f cof.(tt+p+Y)=-^coi.(e+0 -*co£<-/ (F). 



Cc & Addi- 



