Learning to use GeoGebra

During the Covid-19 lockdown, I am trying to challenge myself (and eventually others) to learn how to use the dynamic geometry app GeoGebra, which I usually mention when I do workshops for teachers and parents.

I used a one-person zoom meeting (of all things!) as an environment in which I could create a video showing me in the process of learning the app to demonstrate one of my favorite geometry situations.

Please take a look at the video, try GeoGebra yourself, and use the comment option here to tell me what you conjecture.

If this works out, I will be encouraged to create additional videos for challenge and enjoyment.

Here's the video: https://youtu.be/7BbPbqRIHsA