https://teacher.desmos.com/activitybuilder/custom/5f3854906c476e0c62e44c96
Its not yet integrated with the computational layer, so you can’t do anything too fancy yet, but still some good promising uses I think.
Vector Stuff Using Geometry Tool in Desmos Activity Builder
Teach. Brian. Teach. 
Nice! How did you get the lengths of the vectors to show up as dynamic labels? I can’t seem to find that in the documentation.
It’s clunky, You need to do segment and vector and top of each other and label the segment