Brunheira, LinaPonte, João Pedro da2023-04-182023-04-182015Brunheira, L. & Ponte, J. P. (2015). Prospective teachers' development of geometric reasoning through an exploratory approach. In K. Krainer & N. Vondrová (Eds.), Proceedings of the Ninth Conference of the European Society for Research in Mathematics Education (CERME9, 4-8 February 2015). Prague, Czech Republic: Charles University in Prague, Faculty of Education and ERME. https://hal.science/hal-01286995/documenthttp://hdl.handle.net/10400.21/15900We aim to characterize how prospective teachers perform in defining and classifying quadrilaterals through working on exploratory tasks. Data was gathered from the participants’ reports and portfolios. Results show most understood the meaning of defining and presented correct definitions, using properties they previously ignored, and showing comprehension of the underlying concepts. They produced economical definitions in few cases, and performed better in inductive than deductive reasoning. The classifications showed conflicts between prior classifications and structural criteria that rules a geometrical classification. The exploratory work allowed participants to construct their knowledge in a meaningful way and reflection played an important role in becoming aware of personal preconceptions and knowledge.engTeacher educationGeometryGeometric reasoningExploratory approachconference object