Descriptive Geometry: The Sphere

This lecture covers the topic of descriptive geometry applied to spheres, focusing on the sections of a sphere by planes. It explains how to obtain both large and small circles as sections of a sphere by different planes. The lecture also discusses the intersection of a straight line with a sphere, detailing the construction of intersection points using auxiliary planes. Various examples and exercises are provided to illustrate the concepts, such as finding intersection points between a sphere and a line. The lecture concludes with the construction of intersection points by projecting a line onto a sphere, emphasizing the practical application of descriptive geometry in solving geometric problems.