160 A N N TAT 10 N E S 



Coroll. i. 



Cum fit CF. EF:=FQ? erit CF : FQ==FQj EF, 

 vnde ducla redta QE^ fiet triangulum FQE fimile 

 triangulo FCQ, vel ECV, ideoque angulus FQE 

 aequalis angulo ECV, 



Coroll. 2. 



Cum fit CE : E V == EO : EF , pundura F 

 etiam ita definiri poterit : ex O ducatur recta ad CV 

 productam normalis , eaque bafi CE in F occurret, 



Coroll. p 



Si prlygonum circulo ENM circumfcriptum f\% 

 n laterum, erit angulus ECP=r* , denotante v. men- 

 furam duorum angulprum redorum \ et angulus 

 FCQr % Hmc fi radius CE=r, ent EP=nang.J- 

 et FQ=Cimng»-. 



Coroll, 4, 



Iam quia angulus FQE:='fi erit EF— FQtang.f; 



=rlrtang.J-tany.^. Verum fi vocemus CF~j, erir, 

 F Q= s tang. Jj , \nde ob F Qz= \ r tang. \ fiet 

 j—^rtang^cot *. 



Demonftratio 

 Conftruftionis Cartefianae, 



F - . Sit iam CE radius circuli quadrato infcripti, CF 



oftogono infcnpti, CG polvgono regulari \6 laterum ? 



CH 



