Accreditation is a process in which school standards are evaluated by an accreditation agency. In the United States, this process is not completed by the federal government, but by states or private companies with varying rules and standards. Different groups promote accreditation for homeschoolers.
The circle is the simplest and best known conic section. As a conic section, the circle is the intersection of a plane perpendicular to the cone's axis. The geometric definition of a circle is the locus of all points a constant distance r {\displaystyle r} from a point ( h , k ) {\displaystyle (h,k)} and forming the circumference (C).
Meanwhile this might help. The directrix of a conic section is the line which, together with the point known as the focus, serves to define a conic section as the locus of points whose distance from the focus is proportional to the horizontal distance from the directrix, with r being the constant of proportionality.