[631.] III.
[632.] IV.
[633.] V.
[634.] VI.
[635.] VII.
[636.] VIII.
[637.] PROPOSITION I. Theoreme.
[638.] Demonstration.
[639.] PROPOSITION II. Theoreme.
[640.] Demonstration.
[641.] Corollaire I.
[642.] Corollaire II.
[643.] Corollaire III.
[644.] PROPOSITION III. Probleme
[645.] Demonstration.
[646.] Corollaire I.
[647.] Corollaire II.
[648.] Definition.
[649.] PROPOSITION IV. Theoreme.
[650.] Demonstration.
[651.] PROPOSITION V. Theoreme.
[652.] Demonstration.
[653.] Corollaire.
[654.] Definition.
[655.] PROPOSITION VI. Theoreme.
[656.] Demonstration.
[657.] Définitions. I.
[658.] II.
[659.] Corollaire.
[660.] PROPOSITION VII. Théoreme.