The Pentagon Problem: Geometric Reasoning with Technology
We value the use of technology in mathematics learning and teaching, and we want students to reason and to explore mathematical ideas in their mathematics courses. In recent years, such computing tools as The Geometer's Sketchpad (1991) and Cabri Geometry II (1994) allow us to devise and operate on geometric figures similarly as symbolic manipulators allow us to work with algebraic expressions. In this article, we call these tools figure manipulators. These tools make it possible for students to explore and connect geometric ideas from synthetic, analytic, and transformational perspectives. Yet we wonder how we can actually get this synthesis to happen in our classrooms. Our doubting colleagues, and we, question the effects of such experiences on our students' understanding of mathematics in general and of geometry in particular.