# AP Board 9th Class Maths Notes Chapter 5 Co-Ordinate Geometry

Students can go through AP Board 9th Class Maths Notes Chapter 5 Co-Ordinate Geometry to understand and remember the concepts easily.

## AP State Board Syllabus 9th Class Maths Notes Chapter 5 Co-Ordinate Geometry

→ To locate the exact position of a point on a number line we need only a single reference.

→ To describe the exact position of a point on a Cartesian plane we need two references.

→ Rene Descartes a French mathematician developed the new branch of mathematics called Co-ordinate Geometry.

→ The two perpendicular lines taken in any direction are referred to as co-ordinate axes. © The horizontal line is called X – axis. → The vertical line is called Y – axis.

→ The meeting point of the axes is called the origin.

→ The distance of a point from Y – axis is called the x co-ordinate or abscissa.

→ The distance of a point from X – axis is called the y co-ordinate or ordinate.

→ The co-ordinates of origin are (0, 0).

→ The co-ordinate plane is divided into four quadrants namely Q1, Q2, Q3, Q4 i.e., first, second, third and fourth quadrants respectively.

→ The signs of co-ordinates of a point are as follows.
Q1: (+, +) Q2: (-, +) Q3: (-, -) Q4: (+, -).

→ The x co-ordinate of a point on Y – axis is zero. → The y co-ordinate of a point on X – axis is zero.

→ Equation of X – axis is y = 0

→ Equation of Y – axis is x = 0

→ In a co-ordinate plane (x1; y1) ≠ (x2, y2) unless x1 = x2 and y1 = y2.