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GCT Guide

Michael P. Hitchman
Mathematics Department
Linfield University
McMinnville, Oregon, USA
December 3, 2020

This activity guide complements material in Geometry with an Introduction to Cosmic Topology. In this guide students can use Sage cells to work with complex numbers and transformations of the extended complex plane, and Geogebra to develop dynamic compass and ruler constructions for studying features in Euclidean, hyperbolic, and elliptic geometries. The guide provides several worksheets for student group work or independent study with Geogebra. This activity guide was authored in PreTeXt and, along with the textbook, is freely available at