I can think of several more ways to model the chute. The technique
used would depend on what the end goal was and the surrounding
parts that I would be designing in context of and taking the best
advantage of that.
Anna thanks for the suggestions. I am actually trying to
close the end semi-perpendicular to the one you have closed. Its
like a double compound angle.
create an edge flange (per jpeg), then edit the flange sketch.