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Fellows Engaged as Resources in Mathematics to Assist Teachers


Lesson Name: Taxi-cab Metric B - Circle

Class: Geometry

Grades: 7-8

Resources:  Regular_city_2.gsp. Note: in order to view and use this file you need to have a Geometry Sketchpad installed in your computer.

Note: This is the second part of the lesson Taxi-cab Metric and you need to do this only after introducing the taxi-cab metrict.

Outline:  Create a circle using the taxi-cab metric.

Begin with a discussion of definitions.  What makes a circle a circle?  What makes other geometric figures, those geometric figures.  If the students are too attached to the visualizations of the figures they are working with they will have more trouble accepting a taxi-cab circle as an actual circle.  (This may take a lesson in itself.)

Step 1:  (~10 min)  How are you going to approach the problem?  Discuss different methods for figuring out how to graph the circle.

Step 2:  (~15-20 min)  Implement what you discussed in step 1.

Goals: Seeing the importance of definitions over visualizations.

Implementation:  Draw various figures both geometric and otherwise and ask the students what shapes they are and why.

For graphing the circle discuss how to make a t-chart of points to get a general idea of what the circle looks like.


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