1. The problem statement, all variables and given/known data What type of region(s) do the following classify as? 2. Relevant equations 3. The attempt at a solution I would classify D1 as both types; my reasoning is that by the definition of a convex polygon (i.e. all x,y in D1, the lie segment connecting x and y is entirely in D1), this therefore qualifies as both types. For D2: Let c be a point in interval between x-value endpoints of region, cross section of D2@c, projected onto y-axis is closed interval and depends on c continuously. (This is true for an arbitrary c in between y-value endpoints), so would this be both types as well?