conclusion arises from the manipulation of vertices “E and G under the conditions
described in the problem”. However, moving E and G, we observe that the segment
GH isn’t always parallel to the side AB of the rectangle but GeoGebra indicates that the
length of this segment is always “13”. This may be a consequence of the default
rounding – in this case, round to the unit – which, most likely, was overlooked by the
participants.
The team revealed its technology fluency in their flexible use of GeoGebra, not only to
represent the situation posed, but to obtain the solution and to attempt an interpretation.
Although they are somewhat fluent in terms of mathematical knowledge, they seem to
be convinced that the length of the segment GH is also invariant, which is not.