This study investigated the actual learning processes of two preservice teachers as they explored geometry problems with dynamic geometry software and the effects of using the software on developing their mathematical reasoning and proof abilities. A constructivist teaching experiment was designed and implemented for the investigation. Through…

This paper reports on a series of four studies carried out over a period of four years. These related studies were clinical and qualitative as they investigated middle and high school students' development of geometric thought, particularly as it related to three- dimensional visualization. The studies were carried out in the constructivist…

Describes the angles-of-a-star problem designed to find the sums of the measures of the angles at the vertices of a five-pointed star. Shows that a good problem may have many correct solutions. (KHR)