The following will find the sum of the interior angles of a triangle and the sum of the remote interior angles of a triangle. Students can then change the type of triangle. The student will see that the sum of the interior angles is always 180 degrees. Also, the student will see that the sum of the two remote interior angles is equal to the exterior angle.
Before the Activity
Make copies of the handout, if needed. All students will need a TI-Nspire™.
During the Activity
Have students make the construction as described in the handout. It may be easier to have students work in pairs to help with the construction.