Cartesian System

A point is located by referring to two perpendicular lines in a Cartesian system. The X-axis is the horizontal line XX’, and the Y-axis is the vertical line YY’.

Origin
The origin, indicated by the letter ‘O,’ is the place where the horizontal and vertical lines intersect.

Coordinate Axes and Quadrants

The plane is divided into four sections by the X and Y axes. The quadrants (one-fourth section) are numbered I, II, III, and IV in anti-clockwise order from OX

Points in Different Quadrants

Signs of coordinates of points in different quadrants:

I Quadrant: ‘+’ x – coordinate and ‘+’ y – coordinate. Eg. (2, 3)

II Quadrant: ‘-’ x – coordinate and ‘+’ y – coordinate. Eg. (-1, 4)

III Quadrant: ‘-’ x – coordinate and ‘-’ y – coordinate. Eg. (-3, -5)

IV Quadrant: ‘+’ x – coordinate and ‘-’ y – coordinate. Eg. (6, -1)

Plotting on a Graph

Point A is represented by an ordered pair (x, y) where x is the abscissa and y is the ordinate of the point.

Plotting a Point in the Plane if Its Coordinates Are Given

For example, Point (3, 2) is 3 units away from the positive y-axis and 2 units away from the positive x-axis. Therefore, a point (3, 2) can be plotted below. Similarly, (-2, 3), (-1, -2) and (2, -3) are plotted.