MOTVS FLVIDORV M 285 



ficque numerus bafium inueftigandarum , vnitate eft im- 

 minutus. 



33. Iam triangulum pqr reperitur , fi a rlgura 

 TprqQ_ t feu a fumma trapeziorum PprR-f-Rr^Q^ 

 auferatur trapezium PpqQ_; vnde erit 



A/>?r=iPR(Pp-+-Rr) + |RQCRr-+-QfHPQ(ty+Q0 ; 

 fiue ob PR = R; RQ— Q-R; et PQ=zQ erit. 



ApqrzzziR(?p--Qq) + kQ_(Rr-?p)zzzlQj<-iRq. 

 Simili modo erit : 



A^/=SPS(P/»-hSj)-*-sSQ{Sj-f^)-sPQ(Ii)+^),fcO 



A^=iS(Pp-+Sj)+-i(Q-SXS.f-i-Q^-iQ(Pp-f-Q_^) 

 \nde fit : 



Apfj = iS(P/>-Q<flH-sQ(Sj-P# = ft qj-fStf. 

 Ac denique 



A/>rj=iPR(Pp+Rr)-f-jRS(Rr-+-SO-«PS(Pp+-Sj) feu 



Aprir' s R(P^+Rr)+i(S-R)(Rr+Sj)-§S(P^ + Sj) 

 vnde fit: 



A/>ri-iR(Pp-Sj> + iS(Rr-P^) = iSr-|Rj. 



34.. His igitur valoribus fubftitutis , obtinebi- 



mus 



^*^«=(Qr-Rtf)cr-h(S?-Q/)?4-(R.f-Sr)$ 



fiue pyramidis 7r(f>£<x folidftas erit 



i(Qr-R^<r-t-i(S^-Q..f)?-+-i(RJ-Sr>(I> 



Eft autem ex coordinatarum \aloribus fupra §. *8 ex- 



bibitis 



Qzzzdx-\-Ldxdt qzzz Udxdt (pzzzNdxdt 

 Kzzz Idydt rzzzdy-\-mdydt ^zzzndydt 

 S= 'hdzdt szzz [x.dzdt (rzzzdz-Yvdzdt. 



Nn 3 35- 



