Euclid's Elements

All thirteen books of Euclidean geometry. Dependency graphs show how propositions depend on definitions, postulates, common notions, and prior propositions. Cross-book references (Book I, Book II, etc.) are shown explicitly.

Book I — Fundamentals of plane geometry 48 propositions; defs, postulates, common notions Book II — Geometric algebra 14 propositions; rectangles, squares Book III — Theory of circles 37 propositions; 11 definitions Book IV — Inscribed and circumscribed figures 16 propositions; triangle, square, pentagon, hexagon, 15-gon Book V — Theory of proportions 25 propositions; 18 definitions Book VI — Similar figures 33 propositions; 4 definitions Book VII — Number theory 39 propositions; 22 definitions Book VIII — Continued proportions 27 propositions; uses Book VII defs Book IX — Number theory 36 propositions; primes, perfect numbers Book X — Incommensurables 115 propositions; 16 definitions; binomials, apotomes Book XI — Solid geometry 39 propositions; 28 definitions; planes, parallelepipeds Book XII — Measurement of figures 18 propositions; circles, pyramids, cones, spheres Book XIII — Regular solids 18 propositions; five Platonic solids