Worksheet 5, Clip 1, Discussion of Question 1,1:53

• The teacher specifically asks them whether or not the point tells them how far the skier traveled. This helps him make the contrast between the distance the skier traveld (which in this case is arclength) and a point on the circle.
• To help them make sense of the points, he asks them about what the zero means in the problem. He continues the conversation until they speak about the point as giving the vertical and horizontal distance from the origin.
• He prompts them to put a coordinate system on their circle in order to be consistent with their other activities.