9 1. THE REAL PROJECTIVE PLANE §1.1 The Real Affine Plane The Euclidean Plane involves a lot of things that can be measured, such as distances, angles and areas. This is referred to as the metric structure of the Euclidean Plane. But underlying this is the much simpler structure where all we have are points and lines and the relation of a point lying on a line (or equivalently a line passing through a point).
- suitable origin o.
- r3+2r1 r2÷21 r2+31r3
- component by component
- component component
- corresponding values
- line through the origin
- line from origin
- r3
- lines