Elementary question from a non-ref

[eyezen]

Take the point where the free thow line intersects the free throw lane line, draw a line to the point where the sideline intersects the endline. Now add the free throw semi circle.

Anything inside this area goes to the baseline, outside goes to sideline.

Edit:

Looks like Fonzzy07 beat me to it, however don't forget the free throw semi circle is included.