1. The Coordinate Plane
• Chapter 4 Section 4.1
P. 206

2. 5 1, 5
4, 2
-5 5
7, 1
2, 2
-5

3. The coordinate plane is divided
by two number lines. One is
horizontal, like the number line
you already know.

4. -10 -5 0 5 10

5. The other is vertical, with up
being the positive direction and
down being the negative
direction.

6. 5
-10 -5 0 5 10
-5

7. The origin is the
point where the 5
two number lines
meet.
-10 -5 0 5 10
-5

8. The two number
lines have special
5
names.
x
-10 -5 0 5 10
The horizontal
number line is -5
called the x-axis.

9. The vertical y
number line is
5
called the y-axis.
x
-10 -5 0 5 10
-5

10. The plural of axis y
is axes. We often
5
talk about the
coordinate axes.
x
-10 -5 0 5 10
-5

11. To study a point, we need to know
where to find it. So we give it
coordinates.
Coordinates are like an address.
They tell you how you can get to a
point if you start at the origin.

12. Coordinates are y
always written in
parentheses, with 5
x, y
the x-value first.
x
-10 -5 0 5 10
-5

13. Coordinates y
written in
parentheses are 5
x, y
called an
ordered pair. x
-10 -5 0 5 10
-5

14. Consider the
point which has 5
coordinates, (4
, -2)
-10 -5 0 5 10
-5

15. The first number
tells you how far 5
to move to the
side.
-10 -5 0 5 10
-5

16. So the 4 in (4, -2)
says we need to 5
move 4 units to
the right.
-10 -5 0 5 10
Remember to start at
the origin. -5

17. The second
number tells you
5
how far to move
up or down.
-10 -5 0 5 10
-5

18. The –2 in (4, -2)
tells you to move
5
down two units.
-10 -5 0 5 10
4, 2
-5

19. To get to the
origin from the
origin, we don’t 5
move at all.
-5 0 5 10
-10
0, 0
So the origin is
designated by the -5
ordered pair,

20. The two number
In Quadrant I, all
lines divide the
II numbers are
I
plane into four 5
positive.
regions.
-10 -5 0 5 10
In Quadrant III, x- In Quadrant IV, x-
and y-values are values are positive
III -5 IV are
and y-values
both negative.
negative.

21. Give the coordinates of each point:
2, 3
5,1
3, 2 2, 4

22. Tell how you can find each point:
Remember to start at the origin!
8, 7 From the origin, move to
the right 8 units, then
4, 0 down 7 units.
4, 5
0, 9
7,12

23. Use your own words to
explain what each term
means:
origin ordered pair
coordinates
quadrant
axis

24. • Read Section 4.1 – especially about
functions !!
• Assignment: P. 209 1-21
Review Vocabulary from this section