Students will be able to develop and prove hyptheses about angles in triangles, in preparation for the next lesson, in which they will develop a proof of the Pythagorean theorem.

Students work on proving hypotheses – and end up proving the Pythagorean Theorem.

10 minutes

30 minutes

5 minutes

With about five minutes to go, I ask the students to stop working and I let them know that I’d like each group to report out on their progress with the Parallel Lines problem.

- I ask to hear first from any groups who are not yet finished:
- What is their hypothesis?
- Where are they in the problem solving process?
- Are they having any particular issues? If so, with what?
- From groups who have finished, I ask for one observation from each group:
- Did they struggle with anything in particular?
- What did they find challenging?
- Did they find these tasks difficult or easy, and why?