# Patty Paper Geometry

Did you know that one of the ideal manipulatives for geometric investigations is patty paper? It is semi-transparent, holds a crease, and can be writen on with pencil (plus you can use them to separate hamburgers). The author's chance encounter with patty papers in a paper-folding activity led to his use of them in the classroom, where he discovered they were the perfect solution for geometric constructions and explorations. He relates, "When patty paper activities started appearing in my workshops for teachers, I devoted a brief five minutes to them. Within months the number of patty paper activities grew until five minutes became ten, then fifteen, then thirty minutes. I now do three-hour patty paper geometry workshops! Caution: Patty paper geometry is addictive." This well-written book uses a discovery approach along with patty papers to investigate all of the basic geometric principles. These investigations are divided topically into sets such as "Special Points of Intersection" and "Properties of Circles". Within each set are both Guided Investigations and Open Investigations. Guided Investigations have step-by-step instructions with illustrations. Open Investigations encourage independent discovery and include lined spaces for students to record their findings. At the end of each set of investigations there are exercise sets to reinforce new concepts and review previously-learned concepts. Answers to all course exercises and questions are also included. Although student pages in the text are reproducible, a nicely formatted consumable student workbook is also available. It contains all of the open investigations and most of the exercise sets. We are also happy to be able to offer patty papers to use with this course (A big thanks to Hilary and Michael here for all the trouble they went through to locate and finalize arrangements to make this possible).

This course would be equally suitable for use as a supplement to a formal geometry course or as a pre-geometry text. If you are using Discovering Geometry as your basal text there will be some overlap, since that book also uses patty paper investigations throughout the course.