The problem is

Draw Triangle ABC. Construct Midpoint D of side BC. Draw median of AD.
I got up to this part on sketchpad, but then it asks what the invariant is. I can't find an invariant.
It also asks to find segments whoses lengths are in constant ration

and then aks are there any invariant areas? ratios of ares?

It says also to then provide another invariant and to provide a chart or table of measurments

Can any one help me understand this problem?