case 1

Protractor Applet, Clip 1, Applet Discussion, 3:44

In this clip the teacher imitates a discussion about the applet.

Protractor Applet, Clip 2, Moving Ray, 3:28

In this clip the teacher uses the mouse to move the ray.

Protractor Applet , Clip 3, Changing Radius, 1:59

In this clip the teacher involves the students in a discussion about what happens with the angle measure if the radius of the circle is increased.

Protractor Applet, Clip 3, Changing Radius, 1:59

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  • The teacher asks what will happen with the angle measure as the radius of the circle is increased.
  • The teacher asks the students to identify which measures are changing (and which are not).
  • The students are able to correctly identify which are changing and which are not. The teacher takes the opportunity to discuss why they may (or may not be) changing before actually changing the size of the radius on the applet.
  • Notice how the teacher makes use of the measurements on the applet and constantly draws the students' attention to their meaning.
  • Also, the teacher is constantly reinforcing the language the students are expected to use in the classroom. This type of reinforcement will help constitute the classroom norms for angle measure.