It could be a pyramid.
Because polyhedron means 'many faces' - a polygon is a two-dimensional shape - it only has one face.
A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.
A polygon must be a 2-dimensional object so it cannot have any thickness (such as a sheet of paper), not can it have any curvature. So a picture on your TV screen - but only if it is a flat screen - is likely to be one of the few true examples.
A polygon is a 2-dimensional figure bounded by three or more straight lines. Any one of its sides may be considered a base.
A circle is one example of a plane figure that is not a polygon. A V is also not a polygon.
It could be a pyramid.
This question is very difficult to answer because of the ambiguity of what an "arrow" is. An arrow that you might fire from a bow is a three dimensional object and so is not a polygon. An arrow drawn as a straight line with a direction indicator at its head with or without tail feathers (for example <|----<< : oh, the graphics on this browser are so good, aren't they!) is not a polygon because the shaft is a line: a 1-dimensional object. An arrow such as the default one used to represent the cursor in Windows is a concave heptagon.
Because polyhedron means 'many faces' - a polygon is a two-dimensional shape - it only has one face.
It can be a triangular based pyramid
A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.A square is a 2-dimensional object. It has only one face and four sides.
A polygon must be a 2-dimensional object so it cannot have any thickness (such as a sheet of paper), not can it have any curvature. So a picture on your TV screen - but only if it is a flat screen - is likely to be one of the few true examples.
A polygon is made up only of line segments. If a 2-dimensional closed figure has even one curve line, then it is not a polygon.
A parallelogram is a 2-dimensional object. It has only one face and four sides.A parallelogram is a 2-dimensional object. It has only one face and four sides.A parallelogram is a 2-dimensional object. It has only one face and four sides.A parallelogram is a 2-dimensional object. It has only one face and four sides.
A line.
line
A polygon is a 2-dimensional figure bounded by three or more straight lines. Any one of its sides may be considered a base.