The first edition of Experiencing Geometry was published in 1995. It was a result of Prof. Henderson’s 20-year experience of teaching geometry and honing his unique teaching style. While preparing 4th edition of this book in his memory, I went through his notes and journals from the 1970’s which gave me an insight into how deeply he was […]

In her session, titled “Adapting Tasks for Increased Interactivity” Claudine will be  sharing a digital task sequence developed in collaboration with Steve Boyce. Steve developed the initial set of tasks as a Word doc and then redeveloped it as a GeoGebra classroom activity. The latest version is built as a Desmos classroom activity and incorporates new […]

We’ll discuss using a Euclidean geometry course as a vehicle for teaching the processes of doing mathematics. I’ll assert that geometry is a good place to invite students into the culture of being a mathematician, and share some techniques for getting students to learn not just how to find a proof, but how to state […]

Over the last several years, the Teaching GeT Working Group members of the GeT: The Pencil community have been engaged in writing a set of essential Student Learning Objectives (SLOs) for Geometry for Teachers (GeT) courses. In this seminar, members of this working group will provide a historical lens on the development of the SLOs […]

With the GeT Community coalescing around a set of student learning outcomes for GeT courses, the next discussion on the horizon is how and when GeT instructors (that is, geometry teacher educators) develop the knowledge needed to teach GeT courses. This talk will explore some of conceptualizations of mathematical knowledge for teaching teachers and will open up […]

The main theme of this talk is connections built and lost within and across geometries with a look into historical reforms in school geometry. The presentation has three parts. First, I exemplify my classroom experiments to advance teachers’ knowledge of connections between different geometries by making familiar objects unfamiliar in alternative geometries. Definitions and the […]

This 1-hour informational online seminar is meant to engage with those who are interested in contributing to the volume “The GeT course: Resources and Objectives for the Geometry Courses for Teachers.” During this seminar, the editors of the upcoming volume will present their vision and overall objectives for the book, as well as answer questions you […]

In Euclid’s Elements, the exterior angle theorem (Proposition 1.16) states that the measure of an exterior angle of a triangle is greater than either of its remote interior angles. This theorem is valid in Euclidean geometry and hyperbolic geometry, but not valid in spherical geometry. Indeed, the proof for this theorem originally presented in Elements […]

Exploring hyperbolic geometry in a GeT course can enrich the student experience by offering a contrast to the more familiar Euclidean world.  In a geometry where lines have very different properties than in Euclidean geometry, students are forced to reconsider what they consider to be “true” or “obvious”.  On the other hand, conceiving of a […]

Proof-writing is a core practice of mathematicians and a crucial skill every future teacher and mathematics major needs to acquire. A proof-based geometry course provides a fruitful ground for developing proof-writing skills. Despite recent pedagogical and technological advances proof remains difficult to learn and to teach. We conducted a pilot study to explore potential advantages […]