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