This chapter introduces the 2-D Cartesian coordinate system by weaving together its ancient historical origins in India and its modern mathematical applications. It explains how a structured framework of perpendicular x and y axes allows us to identify any location using a pair of numerical values, known as coordinates, which originate from a central point called the origin. By utilizing a practical example of mapping a bedroom for a visually impaired student, the source demonstrates how these concepts help us visualize algebraic equations as geometric shapes. Furthermore, it details how to compute the distance between two points using the Baudhāyana–Pythagoras Theorem, providing a comprehensive foundation for understanding how points, lines, and shapes interact within the four quadrants of a plane.