[51.] PROBLEMA I. PROPOS. 1.
[52.] COROLLARIVM.
[53.] PROBLEMA II. PROPOS. II.
[54.] PROBLEMA III. PROPOS. III.
[55.] SCHOLIVM.
[56.] THEOREMA I. PROPOS. IV.
[57.] COROLLARIVM I.
[58.] COROLLARIVM II.
[59.] THEOREMA II. PROPOS. V.
[60.] THEOREMA III. PROPOS. VI.
[61.] COROLLARIVM.
[62.] THEOREMA IV. PROPOS. VII.
[63.] THEOREMA V. PROPOS. VIII.
[64.] COROLLARIV M.
[65.] THEOREMA VI. PROPOS. IX.
[66.] COROLLARIVM.
[67.] THEOREMA VII. PROPOS. X.
[68.] THEOREMA VIII. PROPOS. XI.
[69.] COROLLARIV M.
[70.] LEMMA PRO ANTECED. PROP.
[71.] THEOREMA IX. PROPOS. XII.
[72.] COROLLARIV M.
[73.] THEOREMA X. PROPOS. XIII.
[74.] THEOREMA XI. PROPOS. XIV.
[75.] THEOREMA XII. PROPOS. XV.
[76.] SCHOLIVM.
[77.] THEOREMA XIII. PROPOS. XVI.
[78.] COROLLARIVM.
[79.] THEOREMA XIV. PROPOS. XVII.
[80.] COROLLARIVM.