1. Notes 21
The Coordinate Plane
5-1

2. Vocabulary
Coordinate plane- a plane containing a horizontal number line and a vertical number line.
X-axis- the horizontal number line on a coordinate plane.
Y-axis- the vertical number line on a coordinate plane.
Origin- the intersection of the x-axis and y-axis.
Quadrant- the four regions of the coordinate plane, which are numbered I,II,III,IV.
Ordered pair- consists of two numbers in a certain order.

3. x y
A coordinate plane is a plane containing a horizontal number line, the x-axis, and a vertical number line, the y-axis. The intersection of these axes is called the origin. 5
y-axis 4
Quadrant II 3
Quadrant I 2
x-axis 1 –5 –4 –3 –2 –1
Origin 1 2 3 4 5 –1 –2
Quadrant III –3
Quadrant IV –4 –5
The axes divide the coordinate-plane into four regions called quadrants, which are numbered I, II, III, and IV.

4. Additional Example 1: Identifying Quadrants on a Coordinate Plane
Identify the quadrant that contains each point. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. S W
S lies in quadrant IV. T
B. T
T lies in quadrant I.
C. W S
W lies on the y-axis
between Quadrants I and II

5. On your own. Highlight the answer.
Check It Out: Example 1
On your own. Highlight the answer.
Identify the quadrant that contains each point. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. N N
B. X Y
C. Y X

6. x y –2 2 –4 4 –1 –3 –5 5 3 1
Points on a coordinate plane are identified by ordered pairs. An ordered pair consists of two numbers in a certain order. The origin is the point (0,0).
2 units up
3 units
right
Ordered pair
(3, 2)‏
x-coordinate
y-coordinate
Units right
or left from 0
Units up
or down from 0

7. Additional Example 2: Plotting Points on a Coordinate Plane
Plot each point on a
coordinate plane. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. D (3, 3)‏ D
Start at the origin. Move
3 units right and 3 units up.
B. E (–2, –3)‏
Start at the origin. Move
2 units left and 3 units down. E F
C. F (3, –5)‏
Start at the origin. Move
3 units right and 5 units down.

8. On your own. Highlight the answer.
Check It Out: Example 2
On your own. Highlight the answer.
Plot each point on a
coordinate plane. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. D (4, 4)‏
B. E (–2, 3)‏
C. F (–1, –2)‏

9. Additional Example 3: Identifying Points on a Coordinate Plane
Give the coordinates
of each point. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. X
(–2, 5)‏ X
Start at the origin. Point X
is 2 units left and 5 units up. Y
B. Y
(–1, 0)‏
Start at the origin. Point Y is
one unit left on the x-axis. Z
C. Z
(3, –3)‏
Start at the origin. Point Z is 3 units right and 3
units down.

10. On your own. Highlight the answer.
Check It Out: Example 3
On your own. Highlight the answer.
Give the coordinates
of each point. x y –2 2 –4 4 –1 –3 –5 5 3 1
A. L N L
B. M M
C. N