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The Coordinate Plane
Lesson 9
The Coordinate Plane
Quadrant
Quadrant
II
I
Origin
Quadrant
X-axis
Y-axis
X-axis
Quadrant
Quadrant
III
IV
Y-axis
The Coordinate Plane
Quadrant # ……
(-2,4) *
* (1,2)
(X,Y)
Always read
the X axis first,
followed by the
Y axis.
X-axis.
(-3,-2)
*
* (4,-5)
Y-axis.
The Coordinate Plane
Using a post-it
A (2,-1)
note, mark each
point on the
B (4,-2)
coordinate plane
C (-5,1)
using the correct
letter.
d (-3,-2)
E (-3, 4)
F (1,-2)
G (6,-4)
The Coordinate Plane
Pg. 116
# 1-4,
Challenge:
# 1-2 + 4-6
STOP
The Coordinate Plane
Method 1
Find the distance
between two points
on the same axis.
1. Count the number
of units between 0
and the first point.
2. Count the number
of units between 0
and the second
point.
3. Find the sum of
the two distances
What is the distance
between point
Point
B
A
C
E
D
F
A and
B?
The Coordinate Plane
Method 2
Find the distance
between two points
on the same axis.
1. Write the
coordinates for
each point
2. Subtract the two
points that are on
the same axis from
one another
3. Find the absolute
value of the
answer
A (-2,3)
B (3,3)
C
A
B
-2 – 3=
-2 + (-3) =
-5
D
E
F
Can the distance
between two
points be
negative?
The Coordinate Plane
Reflection
You can use the distance on a coordinate grid
to find the reflection of a point.
The Reflection of a given point across the x-axis
or y-axis is another point with the same
distance from the axis as the given point.
The Coordinate Plane
Which points
are a reflection
of point A?
B C
The Coordinate Plane
You Try!
Pg. 115
# 6-14
Multiplying Integers
Multiplication of integers is the same as
multiplying natural numbers.
The only difference is the product’s sign.
8 * 5 = 40
-8 * 5 = - 40
-8 * -5 = 40
8 * -5 = -40
What patterns do you
see?
Multiplying Integers
X
3
-3
X
- 9
3
-20
1
- 6
- 3
2
1
21
7
X
2
3
14
2
-60
0
0
0
7
1
-40
-1
3
-1
0
0
-20
-2
-2
-7
-1
0
6
20
-14
-2
40
Multiplying Integers
Check Your Understanding
Pg. 121
# 16, 17
*Challenge- 17, 22, 23
Multiplying Integers
At 4 pm the temperature in Clarksville was O
degrees. Over the next 8 hours the temperature
fell at a rate of 3 degrees per hour.
a. Write the rate that the temperature fell as
an integer.
b. Determine the temperature at midnight.
Multiplying Integers
Jilly borrowed $25 from her sister.
a. Write an integer to express the $25 that Jilly
owes her sister.
b. Jilly borrowed $25 from her sister a total of 7
times. Write an expression that represents this
problem.
c. How much money does Jilly owe her sister?
Dividing Integers
Dividing integers is the same as Dividing
natural numbers.
The only difference is the quotient's sign.
8/4= 2
-8 / 4 = - 2
8/-4= -2
-8 / -4 = 2
What patterns do you
see?