Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

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The Missing Link

Workshop 1
Workshop 2
Workshop 3
Workshop 4
Workshop 5
Workshop 6
Workshop 7
Workshop 8


Workshop Sessions 1 & 2

Proportionality & Similar Figures

We are confronted with problems involving proportionality every day. Whether we compare prices in the grocery store, enlarge a photograph to fit in a frame or change the size of a recipe, the basic math concepts are the same. The following lessons introduce students to the concept of proportionality with a variety of techniques to enlarge and reduce figures. Students compare the original drawings with their reproduced images, examining both size and area to learn what "similar" means and to draw conclusions about scale factor. By working with specific figures, students become comfortable with the ideas of proportions and ratios and can use these concepts to solve complex problems. More important, they will know when this type of reasoning is most effective in problem-solving.

Why This Topic Matters

... discover what makes similar figures similar. They are introduced to the concept of scale factor, and they use scale factors to enlarge and shrink figures. Through continued investigations, teachers determine how scale factor affects side lengths, angles, perimeters and areas when figures are enlarged or shrunk.

In Workshop 2: In Practice, Learner Teachers ...

... discuss how their students approached the Proportionality & Similar Figures lessons from Workshop 1. Scoring guides for student work are introduced, and the teachers learn how to sort student work into two categories — meets standards and does not meet standards. Finally, they create new problems to deepen their students' understanding.

On the following pages, we offer agendas for two different levels of professional development:

  • a two-hour workshop, where teachers have an opportunity to watch the program, do one lesson and briefly discuss it
  • a four-hour workshop, where teachers can watch the program, pause the tape after each lesson, do each lesson on their own and have extended discussions with their colleagues

If at all possible, we recommend that you make time for the longer workshop. Even if you don't have time to do all lessons with your colleagues during the workshop, it's essential that you do them on your own between the Discovery and In Practice workshops.

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