When using Coordinate Geometry (COGO) tools in ArcGIS Pro, projection choice influences how distances and bearings are interpreted, where linework is placed, and how boundary areas are calculated. Because projections define how the curved surface of the earth is represented on a flat map, they play a direct role in the positional accuracy and measurement behavior of GIS data. Understanding why projections matter—and how to choose an appropriate one—helps ensure COGO editing behaves predictably without adding unnecessary complexity to the workflow.