GEOMETRIC REASONING OF K-5 IN-SERVICE TEACHERS.

The purpose of this study was to investigate K-5 in-service teachers' geometric reasoning. Twenty teachers completed two types of problem sets. The first consisted of three problems in which participants were to examine three geometric figures, mark which did not belong, and tell why. In the second, participants were to answer five questions on a Venn diagram with three intersecting circles (classify figures in each circle and then draw a figure that would fit into the intersection of all three and one that wouldn't fit into any (with explanation). Developing geometric thinking involves understanding polygons as a class (Battista, 2007; Clements & Battista, 1992). Understanding polygons and relationships among polygons draws on students' ability to recognize and modify relevant attributes of polygons. This process also involves the ability to transform a non-example of a polygon into a polygon (Bernabeu et al., 2021). [ABSTRACT FROM AUTHOR]