Judy Dussiaume and Susan Stuart

Description of the Task The task requires students to classify triangles according to angle and side properties. Students use Geometer's Sketchpad to manipulate triangles to see that constructed triangles have imposed restrictions whereas drawn triangles can be freely dragged to change properties. Students will use mathematical language to describe geometric concepts as they explore, manipulate, and hypothesize about the classifications of triangles.

Students will use geometry to find a hidden constellation in a group of "stars".

Overall Expectations

  • 6m64 identify, describe, compare, and classify geometric figures
  • 6m69 use mathematical language effectively to describe geometric concepts, reasoning, and investigations, and coordinate systems
Specific Expectations
  • 6m75 classify two-dimensional shapes according to angle and side properties (e.g., acute, isosceles)
  • 6m81 use a computer application to explore and extend geometric concepts
  • 6m82 use mathematical language to describe geometric ideas (e.g., obtuse-angled triangle, triangular prism)
  • 6m84 discuss geometric concepts with peers and use mathematical language to explain their understanding of the concepts
  • 6m85 explain, make conjectures about, and articulate hypotheses about geometric properties and relationships
Download full teacher notes (Word) or Download full teacher notes (PDF).

Materials Needed Geometer's Sketchpad needs to be installed on all computers. Four files need to be saved on each computer