An open-ended problem about a circle illustrates how problem-based instruction can enable students to develop reasoning and sense-making skills.
Gloriana GonzÁlez, email@example.com, is an assistant professor of mathematics education in the Department of Curriculum and Instruction at the University of Illinois at Urbana-Champaign. Her research interests include problem-based instruction and the teaching and learning of geometry.
Anna F. Dejarnette, firstname.lastname@example.org, is a doctoral student in the College of Education at the University of Illinois at Urbana-Champaign. She is interested in how students make sense of mathematical ideas.