# Similar Circles 2

- Author:
- Ken Garrabrant

In the app above the pre-image circle (labeled pre) is changed by moving the Radius slider left or right to enlarge or reduce the radius. The center of "pre" is changed by moving the X and Y sliders The red circle is the translated image of "pre" back to the unit circle. The green circle is the Unit circle (a circle centered at the origin with the radius of 1).

Change the radius of "pre" by adjusting the slider right or left. What is the radius you decided to use? What is the scale factor that will dilate "pre" to be the size of the unit circle. Type your answer without any decimals.

Repeat the activity above at least three more times and record your answers below.

Move the sliders for the center of "pre" left or right. What center did you choose? What is the vector that will translate "pre" back to the unit circle?

Repeat this activity at least three times and record your answers below.

Explain how to use transformations to show that all circles are similar. Use a specific example from your activities above.