Is the given shape a polygon?
First, we need to remind ourselves what the definition of a polygon is. A polygon is a plane shape with straight sides. And a plane shape is a shape that is a flat surface with no thickness. The straight sides also must make a closed shape.
Here’s an example of a plane shape that has straight sides but is not closed. This open space means that it’s not a polygon. So we are looking for three things: a plane shape with straight sides that’s closed.
If we look closely at our given shape, is it plane? Is it a flat surface? Yes. Is it composed of only straight lines? Yes. And do those straight lines make a closed figure? Yes, there are no gaps in this shape.
Based on the definition of a polygon, this given shape, this star as we might call it, is a polygon. Is the given shape a polygon? Yes, it is.