The document discusses three dimensional coordinate systems including rectangular, cylindrical, and spherical systems. It provides formulas for finding the coordinates of an internally or externally divided point on a line between two given points. It also discusses direction cosines of lines, including finding the direction cosine of a line from the origin to a given point. Finally, it discusses plane equations and provides a formula for finding the plane equation that passes through three given points, and how to find the vertical distance from a point to that plane.