# CBSE Class 9 Maths Notes for Chapter 3 Coordinate Geometry

CHAPTER 3 COORDINATE GEOMETRY

• To locate the position of an object or a point in a plane, we require two perpendicular l One of them is horizontal, and the other is vertical.

• The plane is called the Cartesian, or coordinate plane and the lines are called the coordinate axes.

• The horizontal line is called the x -axis, and the vertical line is called the y – axis.

• The coordinate axes divide the plane into four parts called quadrants.

• The point of intersection of the axes is called the origin.

• The distance of a point from the y – axis is called its x-coordinate, or abscissa, and the distance of the point from the x-axis is called its y-coordinate, or ordinate.

• If the abscissa of a point is x and the ordinate is y, then (x, y) are called the coordinates of the point.

• The coordinates of a point on the x-axis are of the form (x, 0) and that of the point on the y-axis are (0, y).

• The coordinates of the origin are (0, 0).

• The coordinates of a point are of the form (+, +) in the first quadrant, (–, +) in the second quadrant, (–, –) in the third quadrant and (+, –) in the fourth quadrant, where + denotes a positive real number and – denotes a negative real number.

• If x≠ y, then (x, y) ≠ (y, x), and (x, y) = (y, x), if x = y