POLYGO^^O.IVM RECTILTNEOHVM. 85 



ED— V{Jci -{c Cv^ C -a fin. By) , tumquo 

 F K — <7 cof^ B + f cof. C , hinc aurem fict 



Ahcr :uKe n valnr quo 



^— -v/./8'J-(4-rin.C-flfin.B/)-/?cor.B-^cof.C 

 pro !ioc can.1 fit incon^rnus , quum fit negatiuus 

 m — D' F. Caeterum vt lo'uLi() fit poinb lis , in- 

 telligitnr lunc pr:ie(cr;bi conditioacm , vt habeutur 

 i^ > f fin. C — a fin. B- 



5. Problemn 4. D^z/V o:mifbus qmdrilateri la» 

 Hrlbus et a'!guh B inumrii angulum C. 



Hunc in fincm cuoluarur iile terminus aeqna- 

 tionis noltrac prim.ie , qui continet cof. (B -j- C) , 

 quo fadt ) conleqnemiir : 



dd—aa+ifb-{-cc{-^ a b col.B-fa ^cof.C^^-Ftsfcof.B)— 2 <r a fin.Cfin.B. 

 Vi hinc coRimoJe elici que.u angulus C , ftituamus 

 Tang.F — -li-?^ ita vt fit ^ + acar.B^afiti.Bcot.F, 

 tumque adipi(ccmiir : 



fc^flf^Z>+^r+-2fl£'cof.B+£fl^g-fCcof.Ccof.F-fin Cfin.F), fiu* 

 dd-aa-^rbb-^-cc-V^abcoL^^-^-zac^:!!!!^^!! eft vero 



<a-4-^fr-F-2«6col.B— a'fin.B'cor.F'H-«'fin.B*— «^^'■'•^. 



qiure prodibit 



i^inicr-v-'"^;';^'-^ -- flf g^coC (C-f- F). 



H.iec autetn aequatio in fcquentca facilc transfor- 

 matur : 



