POLYGONORVM RECTILINEORVM. p^ 



tumque 



fin.B-rin.^(B+C)cor.:(B-C)+cof^B+C)rin.;(B-C) 

 cor.B=cor.'(B+C)coU(B-Cj-fin.UB+C)rin.'(B-C) 

 fin.C--fia.|(B-l-C)co(:'(B-C)-co(.'(B+C)rin.-(B-C) 

 cor.C=cof.UB+C)cof:(B-C)+fin.;(B+C)fin.i(B-C) : 



perfpiciemus effe 



flfin.B-<rfin.C:=(^ -^)fin.i(B-f-C)cof KB-C) 



+-(a+-Ocof.HB + C)fin.^(B-C) 



&+-<7ConB + ^cor.C=:^+(^+^)cor^(B+C)corKB-C) 



- (fl - i") ^in. ■ (B +- C) fin. i (B - C) 



ex quo coUigetur fiida neccflliria reduclione 



_ (a-c) fin.i( B+C)- ^ >fin.i(B-C) 

 Tang. KA - D) _ ^^_^^^ ^^,_ . (B+C)+^col. l (B-C)' 



Gietcrum haec formula aliquanto ficilius fic inueni- 

 tnr : quum fic pcr aequationem quartam 



a fin. A -- f fin. D = - ^ fin. (A -f- B) , fiuc 

 cfin.A-^-fin.D = -i-^fin.aA-D+B-C) = ^(fin.;(A-D)corUB-C) 



+co(;:(A-D]fia.i(B-C}) 

 confequimur 



i (^-^)(fin. A+fin.D) + 1 (fl+0(fin.A-fin.D) = 

 (^-^)fin. UA+D) cof ', (A-D)+(«-<r)cof. ' ( A+D) fin. l ( A-D)=: 

 ^'(fin.^^A-D^cof.^B-C^+cof ;(A-D)fin.i(B-C)) , 



\bi fi prLieterea notctur effe 



fin \ (A+0)— fin.^ (B+C) et cof. i(A+D)zr-cof ^ (B+C) 



confequemur 



T V A _ n^ - ^!^^ (B+C) -Mi-U (B-C) 

 iang.,(A ^J-^^+^.cofKB+C)+i;cuf.UB-C)* 



N z Si 



