Circle<span> is the locus of points equidistant from a given point, the center of the </span>circle<span>. The common distance from the center of the </span>circle<span> to its points is called radius. Thus a </span>circle<span> is completely </span>defined<span> by its center (O) and radius (R): C(O, R) = O(R) = {x: dist(O, x) = R}.
Easier explanation: </span><span>A </span>circle<span> is a plane figure contained by one line such that all the straight lines falling upon it from one point among those lying within the figure are equal to one another.</span>
