No it is not a polygon, simply because it is a 3D shape. Yes it has all the other features but it is a 2D shape which is not one of a polygon's features.
Any polygon, other than a triangle, can have 2 parallel sides.
Any polygon, other than a triangle, can have a pair (or more) of parallel lines.
A polygon.
an octagon is a polygon. an octagon has 8 sides. a polygon is a shape with closed sides.
More information is required in order to answer this question. What is the shape for which the perimeter is given? If it anything other than a circle or regular polygon it is not possible to determine the area. For a circle or regular polygon, the answer will depend on the shape.
It could be any irregular polygon other than a triangle.
Depends. "Polygon" is a general term for a shape with more than one side.
Pentagon.
It is called a 'polygon'.
It has less than three sides.
A polygon is a shape with more than two sides. A pentagon has five sides. So a pentagon is a type of polygon.