Explore the concept of perpendicularity in universal hyperbolic geometry through this in-depth video lecture. Discover how duality defines perpendicularity, distinguishing it from classical hyperbolic geometry by allowing points to be perpendicular, not just lines. Learn about altitudes and delve into the collinear points theorem and concurrent lines theorem using homogeneous coordinates and determinants. Examine various examples of viewing planes, perpendicular points, and lines to gain a comprehensive understanding of these advanced geometric concepts.