Math is easy for those who understand it and difficult for those who do not. If one is clear about the basics then going forward is easy and other wise impossible. Here we will try to highlight must know basics and will keep on improving gradually. Circle is a round plane figure whose boundary (the circumference) consists of points equidistant from a fixed point (the centre). Plane Deinition of the circle is "A circle is a plane figure bounded by one curved line, and such that all straight lines drawn from a certain point within it to the bounding line, are equal. The bounding line is called its circumference and the point, its centre".