In mathematics, a Cartesian coordinate system (also called rectangular coordinate system) specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length. Each reference line's called a coordinate axis or just axis of the system, and the point where they meet's its origin. The coordinates can also be defined as the positions of the perpendicular projections o… (More on Y-axis)