Education Technology

Transformation

Published on 06/09/2008

Activity Overview

In this activity, students study different types of transformations.

Before the Activity

Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:

  • TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • TI-Navigator™  "send to class" feature
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 49 - 52 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

    Translation:

  • Construct an asymmetrical polygon
  • Draw a line to the right of the polygon
  • Reflect the polygon across the line
  • Draw a line to the right of the second polygon, and parallel to the first line
  • Reflect the second polygon across the line
  • Identify that when an image is reflected over two parallel lines, the transformation is a translation
  • Measure the distance between the parallel lines
  • Measure the distance between a vertex of the original polygon (pre-image) and its corresponding vertex in the final polygon (image)
  • Measure the distance between one other vertex and its corresponding vertex in the third polygon
  • Observe that the distance between the parallel lines is half the distance of the image and pre-image


  • Rotation:
  • Draw and label a line CD
  • Construct a point A on line CD and draw a line through A
  • Mark a point B on the line through A
  • Construct an asymmetrical polygon in the interior of angle DAB and reflect it across line AB
  • Reflect the new polygon over line AC
  • Identify that when an image is reflected over two intersecting lines, the transformation is a rotation
  • Measure angle BAC
  • Measure the angle between the corresponding parts of the pre-image and image
  • Note that the angle from the pre-image to image is twice the angle of rotation
  • Drag line AC to change the angle between the two intersecting lines
  • Identify that the relationship between the angle from the pre-image to image and the angle of rotation, does not hold true for an obtuse angle because the angle is being read from the other direction
  • After the Activity

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary