Elementary Projective Geometry - Elementary Mathematics Explained

Explore elementary projective geometry in this 36-minute video lecture. Learn about the geometry of lines and straightedges, introduced by Pappus around 300 A.D. Discover basic concepts such as the join of two points, the meet of two lines, and definitions of side, vertex, triangle, and trilateral. Examine a remarkable correspondence between quadrangles and quadrilaterals, focusing on the three diagonal points and diagonal sides. Follow along with the constructions using a pen or pencil and ruler while covering topics like collinear points, useful geometric definitions, and the properties of quadrangles and quadrilaterals. Gain insights into this fundamental geometric approach ideally suited for K-6 education.

Introduction
Requirements for geometry of lines
Collinear points lie on a line
Some more useful definitions
A quadrangle
A quadrilateral