Chapter Four
Plane Projective Geometry
Mathematics may be defined as the subject in which we never know what we are talking about,
nor whether what we are saying is true.
Bertrand Russell (1872–1970)

Section 4.1 -
Introduction
Historical Overview

Section 4.2 -
Axioms and Basic Definitions
(Reference Section 4.6 Definition of Perspectivity and Projectivity)
Basic Theorems    (Exercises 4.1–4.6)
Independence of Axioms     (Exercises 4.9–4.10)

Section 4.3 -
Principle of Duality in Projective Geometry     (Exercises 4.11–4.15)
(Reference Section 4.6 Definition of Perspectivity and Projectivity)

Section 4.4 - Desargues' Theorem     (Exercises 4.16–4.19)

Section 4.5 -
Harmonic Sets    (Exercises 4.20–4.24)
Harmonics and Music    (Exercises 4.25–4.27)

Section 4.6 -
Definition of Perspectivity and Projectivity  (Exercises 4.28–4.29)
Fundamental Theorem     (Exercises 4.30–4.35)
Harmonic Sets and Projectivity   (Exercises 4.36–4.37)

Investigation Activity   (Exercise 4.38)
Alternate Construction of a Projectivity  (Exercises 4.39–4.40)

Section 4.7 -
Conics in the Projective Plane    (Exercises 4.41–4.45)
Pascal's Theorem    (Exercises 4.46–4.50)
Tangent Lines to Point Conics    (Exercises 4.51–4.54)

Chapter Four Exercises. Exercises from all the sections.
Solutions.
Solutions to selected exercises.
Self-Assessment Quizzes. Quizzes for all sections.