Answer
A circle has no sides or vertices. It is a collection of infinite points around a point called the center of the circle. A polygon has sides and vertices. So, a circle is not a polygon.
Work Step by Step
A polygon has different number of sides and vertices. For example, a triangle has three sides, a rectangle has four and a pentagon has five. The dimension of a polygon is the measure of its sides.
On the other hand, a circle does not have any sides. It is made by joining points around a point called as center of the circle. The size (or dimensions) of a circle is measure by the measure of its radius.
As the circle does not have sides, a polygon is not a circle.
