x

y

(x,y)

x - coordinate

y - coordinate

How are coordinates helpful?

A coordinate plane is composed

of a horizontal number line (x-axis) and a vertical number line (y-axis).

(-- , +)

(+ , +)

(-- , --) (+ , --)

y

x

The point where

the two axes intersect is the

origin.

origin

(-- , +)

(+ , +)

(-- , --) (+ , --)

y

x

origin

(-- , +)

(+ , +)

(-- , --) (+ , --)

An ordered pair is a pair of numbers used to name a location on a grid.

y

x

The first number, or the x-coordinate, tells how far to the right or left the point is located in the horizontal direction(x-axis).

(3 , 2)x

y

x

The second number, or the y-coordinate, tells how far up or down the point is located in the vertical direction (y-axis). The coordinates of the origin are (0 , 0)

(3 , 2)y

y

x

The coordinate axes divide the plane

into four regions called quadrants.

QuadrantQuadrant

Quadrant Quadrant

(+ , +)(-- , +)

(-- , --) (+ , --)

y

x

All points in Quadrant I have two positive coordinates.

Quadrant I

(+ , +)

y

x

Quadrant II

(-- , +)

All coordinates in Quadrant II have a negative x-coordinate and a positivey-coordinate

y

x

Quadrant III

(-- , --)

All coordinates in Quadrant III have a negative x-coordinate and a negativey-coordinate.

y

x

Quadrant IV

(+ , --)

All coordinates in Quadrant IV have a positive x-coordinate and a negativey-coordinate.

y

x

Ordered Ordered PairsPairs

Ordered Pairs – are used to locate points on a grid.

The number that is used to represent a point are called coordinates. (2 , 4) are the coordinates on point P.

0 1 2 3 4 5 6 7 8 9 10 11

1

2

3

4

5

6

7

8

9

10

11