A circle is a shape consisting of all points in a plane that are a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves in a plane so that its distance from a given point is constant. The constant distance is called the radius, and the fixed point is called the centre of the circle. In this chapter student will learn about the secant, tangent, a number of tangents to a circle, length of a tangent and so on.