There are no curved edges in a pentagon. Part of the definition of any polygon is that they have straight edges.
it has 0 curved edges
it has 0 curved edges
there are no curved edges on any triangle.
There are no curved edges on a triangular pyramid.
There are no curved edges, but it does stack.
The answer depends on the number of sides in the polygon.
In 3 dimensions, at least, a cube has no curved edges.
1
there are 4 edges
It depends on the polygon
There is one curved side and two curved edges (the rims along the top and bottom).