Lesson objective: Reason to differentiate between geometrically defining attributes and non-defining attributes.
This lesson helps to extend understanding of attributes. Students will describe in their own words why a shape belongs to a given category. A sorting game is used here because it encourages students to engage in problem solving that is about thinking and reasoning. This work develops students' understanding that shapes have both defining and non-defining attributes.
Students engage in Mathematical Practice 3 as they construct viable arguments and critique the reasoning of others. Students will use clear definitions with peers as they define attributes and provide a viable argument reasoning why a shape lacks specific attributes. Students also engage in Mathematical Practice 7 as they look for and make use of structure. Students will use the patterns seen in different shapes to make comparisons. Students will use the relationships demonstrated in the defining attributes to explain similarities and differences.
Key vocabulary:
- attribute
- defining attribute
- non-defining attribute
- sides
- angles
- triangles
