The Coordinate Plane
x axis - horizontal
Terms:
Quadrants
y axis - horizontal
origin - horizontal
Ordered Pair (x, y)
Plot these points:
Q (-3, 1), R (5, 6), S (-2, -4)
>
<
^
v
1 2 3 4 5 6
-6 -5 -4 -3 -2 -1
-1
-2
-4
-3
-6
-5
6
5
4
3
2
1
O
.
y
x
x axis - horizontal number line
Terms:
y axis - vertical number line
origin - intersection
Ordered Pair (x, y)
>
<
^
v
1 2 3 4 5 6
-6 -5 -4 -3 -2 -1
-1
-2
-4
-3
-6
-5
6
5
4
3
2
1
O
.
y
x
The lesson today is on the coordinate plane.
The coordinate plane is basically two number lines put together. One is horizontal and the other one is vertical.
We use them to find the position of a given point on the page.
Let's define some terms as we go along here.
We call the horzontal number line the
x-axis.
Look to the left and you will see that the x-axis is labeled with an x and we've printed its corresponding numbers in red.
The y-axis is the vertical number line. Notice that the y-axis is labeled at the top with the letter y and we have printed its corresponding numbers in green.
The origin is where the two lines cross, or more formally, where they intersect.
Since two lines always intersect at a single point, origin is simply point that the x-axis and the y-axis share in common.
We've labeled the origin O. However, sometimes it is identified by its coordinates, more commonly referred to as an ordered pair.
Plotting Points:
An ordered pair consists of a given point's x-value and y-value.
If we look along the horizontal number line, we see that the origin has an x value of zero (between -1 and 1).
Along the vertical number line, we see that the origin's y value is zero as well (again, between -1 and 1).
So then, the origin can be represented by the ordered pair (0, 0).
To find the location of other ordered pairs (or to graph their cooresponding points), we first moved along the x-axis until we come to the grid mark that lines up with the first coordinate (the first coordinate is always the x-coordinate).
Next, we move up or down parallel to the y-axis until we come to the line that is even with the grid mark corresponding to the second coordinate (which is always the y coordinate).
Doing this correctly places us at our desired location.
.
EXAMPLES
(-3, 1)
Q
.
(5, 6)
R
S
(-2, -4)
.
