Transcript Lesson 10-4a

10-4
6th grade math
Coordinate Graphing
Objective
• To graph and label points in a coordinate plane.
• Why? To know how to correctly read a graph and
an ordered pair, and plot ordered pairs on a
graph; very important skills for your math
career/future. Using equations and ordered
pairs throughout your study of mathematics.
Understanding between a graph and its equation
is an important algebraic skill.
California State Standards
AF 1.4 (Gr. 5) : Identify and graph ordered pairs
in the four quadrants of the coordinate plane.
AF 1.0: Solve simple linear equations, and graph
and interpret their results
MR 2.4: Use a variety of methods, such as …
graphs, tables, … to explain mathematical
reasoning.
Use an ordered pair to represent a point in the
coordinate plane. In the ordered pair (a,b), a
indicates the distance from the vertical, y-axis;
and b indicates the distance from the horizontal,
x-axis.
A positive number indicates a distance is up or
right. A negative number indicates a distance
down or left.
Remember x comes before y, so in an ordered pair,
the order goes x-y.
Vocabulary
• Coordinate graph or grid
– A plane with a horizontal number line, called the xaxis, and a vertical number line, called the y-axis,
intersecting at a point called the origin. Each point
of the grid corresponds to an ordered pair of
numbers.
• 4 quadrants
– The 4 sections of a coordinate graph or grid. I =
(+,+), II = (-,+), III = (-,-), IV = (+,-)
II
III
I
IV
• x-axis
Vocabulary
– The horizontal number lines that are part of the
formation of a coordinate plane
• y-axis
– The vertical number lines that are part of the formation
of a coordinate plane
• Origin
– The point of intersection of the x- and y-axes on a
coordinate graph or grid
→
• Ordered pair
– A pair of numbers used to locate a point on a coordinate
graph or grid (0,-8), (4,3); (-2,1); (-5,-6); (9,-7); (0,0); (6,0)
How to Work with Coordinate Graphs
1) Read and comprehend
the ordered pair.
(starting point = (0,0)
2) The first number in the
ordered pair will start
on the x-axis. + move to
the right of (0,0). –
move to the left of (0,0).
3) The second number in
the ordered pair will tell
you how many units up
or down from the x-axis
to place the dot on the
y-axis.S
graph: A (-2, 4), B (-3, -2)
.
.
A
.
.
.
.
. . . . . . . . . . . . . . . .
B
.
.
.
.
.
.
.
How to Solve and Graph a Table
1) Make a 3-columned table.
Label x, work: equation, and y
2) Under the x, label: -2, -1, 0, 1, 2
3) Solve for x in the work column
4) Answer = y
5) Plot: (x,y)
Graph the equation:
y=x+2
x
X+2
y
-2
-2 + 2
0
-1
-1 + 2
1
0
0+2
2
1
1+2
3
2
2+2
4
Try It!
Complete table and
graph.
7)
x
2x + 1
y
0
2(0) +1 = 0 + 1 1
1
2(1) +1 = 2 +1
2
2(2) +2 = 4 + 2 6
7) y = 2x + 1
8)
8) y = 5 – x
x
5–x
y
0
5–0
5
1
5–1
4
2
5-2
3
3
Objective Review
• To graph and label points in
a coordinate plane.
• Why? You now know how to correctly read a
graph and an ordered pair, and plot ordered
pairs on a graph; very important skills for your
math career/future. You can use equations and
ordered pairs well throughout your study of
math. You can understand a graph and its
equation is an important algebraic skill.
• A coordinate graph or grid can be used to plot
ordered pairs. To plot point (x,y), start at the
origin and move right for a positive x or left for
a negative x, then up for a positive y or down
for a negative y.
Independent Practice
• Complete problems 919
• Copy original problem
first.
• Show all work!
• If time, complete Mixed
Review: 20-26
• If still more time, work
on Accelerated Math.