**7.1 Coordinates**

**7.1.1 Coordinates**

**1.**The

**Cartesian coordinate system**is a number plane with a horizontal line (

**) drawn at right angles to a vertical line (**

*x*-axis**), intersecting at a point called**

*y-*axis**origin**.

**2.**It is used to locate the position of a point in reference to the

*x*-axis and

*y*-axis.

**3.**The coordinate of any point are written as an ordered pair (

*x*,

*y*). The first number is the

*x*-coordinate and the second number is the

*y*-coordinate of the point.

*Example***:**

The coordinates of points

*A*and*B*are (3, 4) and (–5, –2) respectively.This means that point

*A*is located 3 units from the*y*-axis and 4 units from the*x*-axis, whereas point*B*is located 5 units on the left from the*y*-axis and 2 units from the*x*-axis.**4.**The coordinate of the

**origin**

*O*is (0, 0).