What is the difference between an angular and linear skeletal formula?
Those are $sp^2$ carbons and should have a triangular planar 120&deg; geometry. The angles you've drawn are clearly not 120&deg; . 

I've not exactly come across the terminology before, but I believe this is the distinctions:


In a "linear" formula, you disregard the actual bond angles and just try to keep everything in a line.
In an "angular" formula, you draw everything according to the bond angles.


Not sure of this, though.