well it depends on the polygon
The plane at which the incident ray, the reflected ray, and the normal lie is known as the plane of reflection. This plane is perpendicular to the surface of the reflecting object and contains all three of these elements.
A plane.
Plane
A plane mirror doesn't 'really' form an image at all. The image is 'virtual', not 'real'. You see what appears to be an image. It's located at the same distance behind the reflecting surface as the actual object is in front of it. If a real image exists, you can always put a piece of frosted glass, photo-film, or tissue paper where the image is, and capture it. You can't do that with a plane mirror.
a plane
a plane
A flat surface extending in all directions is a plane.
inclined plane
In geometry, a plane is a flat two-dimensional "surface" (similar to a sheet of paper, but with no thickness and no finite length or width). A plane is defined by three points, each of which forms a line with the other two points within the plane. In three dimensions, the simplest version of a plane would include all of the points with any x and y value that contain the same value for z.A plane is a flat surface or a 2-dimensional object, stretching to infinity in all directions.
surface area
A plane
The total area of all surfaces of an object is called the surface area. It is a measure of how much exposed surface the object has.