PLOTTING POINTS ON A CARTESIAN

PLANE

Plotting Points Lesson Objective: Students will know

how to plot points on a plane

Plotting Points René Descartes (1596 – 1650) – Known

for his saying “cogito ergo sum”“I think, therefore I am”

Developed the Cartesian Plane system we use to plot points today. Uses the x and y axis and 4 quadrants

Plotting Points The Cartesian Plane is mostly known as

a “graph” The graph has two axis

The vertical (up and down)is called the y-axisThe horizontal (left to right)is called the x-axis

y

x

Plotting Points There are 4 quadrants to the graph They work from the top

right in a counter-clockwise fashion

y

xIII

III IV

Plotting Points The center of the graph where the two

axis meet is call the

At this point, both the xand y values are zero

y

xORIGIN

Plotting Points The lines on the graph represent one

unit each The x-axis works likes

a linear graph where theorigin is zero and the numbers on the rightare positive, the numberson the left are negative

y

x-4 -3 -2 -1 0 1 2 3 4

Plotting Points The lines on the graph represent one

unit each The y-axis works likes

the x-axis where the positive numbers go upand the negative numbers go down

y

x

4321 0 -1 -2 -3 -4

Plotting Points When you plot a point, you use the

values of x and y to determinewhere on the graphthe point is.

A point always has thex value first, then the y

y

x

yx( , )

Plotting Points To find point A, we have to find where it

is on the x-axis first Then we need to find the

y value So point A is known as

(1, 3)

y

x

A

( , )1

1

3

3

Plotting Points Label point B y

xB

Plotting Points To find point B, we have to find where it

is on the x-axis first Then we need to find the

y value So point A is known as

(-3, 2)

y

xB

( , )-3

-3

2

2

Plotting Points Label points C, D, E, F, and G y

xC

D

E

F

G

You Try!

Plotting Points What is the vertical axis? What is the horizontal

axis? What’s the point in the

middle called? What quadrant is point B

in? What quadrant is Point C For 6 – 10, label the points A – E

C

DE

BA

Quiz!