10-46th 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 x-

axis, 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 I

III IV

Vocabulary• x-axis– 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 Graphs1) 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, 23) Solve for x in the work column4) Answer = y5) 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) y = 2x + 1

8) y = 5 – x

7)

8)

x 2x + 1 y

0 2(0) +1 = 0 + 1 1

1 2(1) +1 = 2 +1 3

2 2(2) +2 = 4 + 2 6

x 5 – x y

0 5 – 0 5

1 5 – 1 4

2 5 - 2 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 9-19

• Copy original problem first.

• Show all work!

• If time, complete Mixed Review: 20-26

• If still more time, work on Accelerated Math.