A right triangle is removed from the rectangle in the figure below.  When the triangle is removed, it creates the shaded region.  Find the  area of the shaded region.

Part I – What is the area of the triangle (20%)
Part II – What is the area of the rectangle (20%)
Part III – What is the area of the shaded region? How did you determine that area? (40%)
Part IV – Review and comment on ONE classmate’s post; provide a comment for each part of the posting. (20%)