In this clip the discussion turns to how things would change if their circle had a different radius.
Worksheet 2, Clip 2, Breaking up Circumference, 3:21
The teacher picks one of the radius lengths they had been using in class to create a sample protractor on the board.
One student suggests measuring the arc with the wikki stix, but the teacher does point out that it can be done without that if you know the radius. To keep the students involved, he allows them to do the calculations. After each calculation he makes sure they are aware of what they have found.
To encourage the students to see how a protractor is constructed, he does NOT allow them to fold the paper or write on the paper. He asks them how they can create a protractor with just wikki stix and a ruler.
One student suggests a (correct) method for finding one degree. The teacher then has a nice discussion about this to focus the students on what it means and how it relates to their protractor. He uses questioning to get the student to state that it is referring to an arclength.
The teacher is constantly pushing the relationship between arc length and angle measure. He does this by using moves such as asking what the .068 refers to and requiring the students to give the units their answers are in.
