[41.] Theor. XII. Prop. XV.
[42.] Theor. XIII. Prop. XVI.
[43.] Theorema XIV. Propos. XVII.
[44.] Theor. XV. Propos. XVIII.
[45.] Theor. XVI. Propos. XIX.
[46.] Problema IV. Propos. XX.
[47.] Christiani Hugenii C. F. ILLVSTRIVM QVORVNDAM PROBLEMATVM CONSTRVCTIONES. Probl. I. Datam ſphæram plano ſecare, ut portiones inter ſe rationem habeant datam.
[49.] Probl. II. Cubum invenire dati cubi duplum.
[50.] Probl. III. Datis duabus rectis duas medias propor-tionales invenire.
[57.] Utrumque præcedentium Aliter.
[58.] Probl. VIII. In Conchoide linea invenire confinia flexus contrarii.
[60.] DE CIRCULI ET HYPERBOLÆ QUADRATURA CONTROVERSIA.
[61.] VERA CIRCULI ET HYPERBOLÆ QUADRATURA AUTHORE JACOBO GREGORIO. LECTORI GEOMETRÆ SALUTEM.
[64.] VERA CIRCULI ET HYPERBOLÆ QUADRATURA.
[65.] PROP. I. THEOREMA. Dico trapezium B A P I eſſe medium propor-tionale inter trapezium B A P F, & triangulum B A P.
[66.] PROP. II. THEOREMA. Dico trapezia A B F P, A B I P ſimul, eſſe ad du-
plum trapezii A B I P, ſicut trapezium A B F P
ad polygonum A B D L P.
[67.] PROP. III. THEOREMA. Dico triangulum B A P, & trapezium A B I P ſimul,
eſſe ad trapezium A B I P, ut duplum trapezii
A B I P ad polygonum A B D L P.
[68.] PROP. IV. THEOREMA. Dico polygonum A B E I O P eſſe medium pro-
portionale inter polygonum A B D L P
& trapezium A B I P.