This activity is designed to give preservice teachers an introduction to the circle, compass and line tools in the Graphs & Geometry application of the TI-NSpire. The set of four investigations are designed to provide them with ideas on how to assess geometric constructions by identifying the different ways these tools can be used. The preservice teachers will explore sketches that appear to be identical but are constructed differently.

Students will need the TNS file loaded into their TI-NSpire or TI-NSpire CAS and a copy of the student activitiy.

Each student should work through the problems using their own hand held, but then discuss their findings in small groups.

The students should create a rubric for grading the Tangent line activity and compare that rubric to their analysis of what the constructions say about a student's understanding of what a tangent line is. There is a follow-up reading from the 2005 NCTM Yearbook Technology Supported Mathematics Learning Environments.