Book I. VIII. IX. X. XI.“ called the circumference, and is such that all straight lines XII. XIII. centre, and terminated both ways by the circumference. XIV. A femicircle is the figure contained by a diameter and the part of the circumference cut off by the diameter, XV. B 2 Book I. XV. XVI. XVII. XVIII. XIX. XX. АДА XXI. XXII. XXIII. XXIV Book I. XXIV. XXV. equal, and all its angles right angles. XXVI. XXVII. are not right angles. XXVIII. another, but all its sides are not equal, nor its angles right XXIX. peziums. Book 1. XXX. which, being produced ever so far both ways, do not meet. POSTULATES. L I. ET it be granted that a straight line may be drawn from any one point to any other point. II. III. may be described from any centre, at any distance from that centre. A X I O M S. M N. T I. II. III. IV. V. VI. Things which are doubles of the same thing, are equal to one another. VII. Things which are halves of the same thing, are equal to one another. VIII. Magnitudes which coincide with one another, that is, which exa&ly fill the same space, are equal to one another. IX. X. “ Two straight lines, which interfect one another, cannot be “ both parallel to the same straight line." |