Girl in the mirror
How large does a mirror need to be to see your full body? Move the girl and use the checkboxes to find an answer to this question. You may want to use the Relation Tool to get reliable answers from the computer when comparing objects.
Note that it is possible to drag the point at the girl's eyes. This shows that the statement does not depends on the position of the eyes.
Some objects may not be comparable due to technical reasons in your browser. Please use the desktop version of GeoGebra in case you run into problems, and download this material to your computer.