Activity: Exploring Dilation
Dilation
Explore the effect scale factor has on the dilation of the image below.
Increase or decrease the scale factor using the scroll bar (e).
You should notice...
Smaller images come from scale factors less than one while the bigger images correspond to scale factors larger than one.
The preimage can be considered a scale factor of 1.
All of the images have the same angles and orientation in the plane.
Dilation with center in the shape
Next
Follow the steps to explore a dilation with the applet below.
Step 1: Use the Dilate tool to dilate Triangle ABC. Center the dilation at point D and use a scale factor of your choice.
Step 2: Using the move tool, change the position of the center of dilation, point D.
Consider the following questions:
1) What happens to the triangles as the center of dilation moves?
2) Why does it look like the triangle is translated after the dilation?
3) Where would the point of dilation need to be to prevent changing the position of Triangle ABC?
Finding Center of Dilation
In the applet below, triangle ABC has been dilated to construct triangle A'B'C'. Use the tools given to complete the following tasks.
1) Develop a strategy for finding the center of dilation. (Hint: think about strategies used to find defining information in other transformations).
2) Verify that Triangle ABC is similar to Triangle A'B'C'.
3) Find the scale factor of the dilation.
Finding center of Dilation
Make sure to record your observations about the effects of scale factor in dilation and how the center of dilation effects the image.
Close GeoGebra and return to Edio to continue on with today's lesson.