Mystery Number: What Does it Tell Us?

Shown below is is a list of points. Note the mystery number "r" changes as you move them. Drag them around for a bit. As you do, pay attention to the value of this mystery number.
What do you notice? What do you wonder? List any observations you see below.
If possible, move these points around to make the value of "r" as high as you possibly can. Then answer the question that follows.
Is there a maximum possible value for [i][b]r[/b][/i] ? If so, what is it?
If possible, move these points around to make the value of "r" as low as you possibly can. Then answer the question that follows.
Is there a minimum possible value for [i][b]r[/b][/i] ? If so, what is it?
Is it possible to get r = 0? Try it!
Can you get r = 0 in a way different from above? Try it!
What exactly does this value [b][i]r[/i] [/b]tell us? How would you describe it? [br]Describe as best as you can in your own words.
Close
– GeoGebra Team, Tim Brzezinski

Information: Mystery Number: What Does it Tell Us?