This document provides instructions on reflections across the x-axis and y-axis of the coordinate plane. It defines reflection as the mirror image produced by flipping a figure over a line. When reflecting a point across the y-axis, the y-coordinate stays the same and the x-coordinate changes sign. When reflecting across the x-axis, the x-coordinate stays the same and the y-coordinate changes sign. Examples are given of reflecting points across the axes and finding the new coordinates. Practice problems are also provided to have students name the reflected points for given coordinates.

1. Name _________________________________ Date _____________________
Mrs. Labuski / Mrs. Portsmore Period _______ Unit 11 Lesson 3 Reflections
OC 2-4
VOCABULARY DEFINITION EXAMPLE
REFLECTION
PRIME
You can use what you know about number lines and opposites to compare locations on the
coordinate plane. Consider the number line and coordinate plane below.
The number line shows that -4 and 4 are opposites.
The coordinate plane shows that the points (-4,0) and (4,0) are the
same distance from the y-axis in opposite directions. So, they are
reflected across the y-axis. Notice that the y-coordinate did not
change and that the x-coordinates are opposite.
When a point is flipped over the y-axis, the ______________will stay the same and only
the ______________ in the ordered pair will change
When a point is flipped over the x-axis, the ______________ will stay the same and only
the ______________ in the ordered pair will change.
AA
ʹ
A

2. Name the ordered pair that is a reflection of (-3,2) across the x-
axis.
To reflect across the x-axis, keep the same x-coordinate, -3, and take
the opposite of the y-coordiante. The opposite of +2 is -2.
So, (-3,2) reflected across the x-axis is located at ______________
Now you try!
Name the ordered pair that is a reflection of each point across the x-
axis.
1. (1,-4) ________________ 2. (-2,5) _____________ 3. (-3,-1) _________________
Name the ordered pair that is a reflection of each point across the y-axis.
1. (1,-4) ________________ 2. (-2,5) _____________ 3. (-3,-1) _________________
Refer to the diagram below to answer the following questions.
1. What is located at the reflection of (-3, -4) across the y-axis?
What are the coordinates of this location?
________________________________________
2. What is located at the reflection of the science labs across the
x-axis? What are the coordinates of this location?
________________________________________
Refer to the map to answer the following questions.
1. What is located closest to the origin? ____________
2. Liza is standing at (2,4). What is located at the
reflection of (2,4) across the x-axis? What are the
coordinates of this location?
________________________________________
3. What is located at the reflection of (3,1) across the y-
axis? What are the coordinates of this location?
________________________________________
4. The Pipeline Plunge is reflected across the x-axis.
What are the coordinates of its new location?
________________________________________
A
ʹ
A

3. Name _________________________________ Date _____________________
Mrs. Labuski / Mrs. Portsmore Period _______ Unit 11 Lesson 3 Reflections
OC 2-4
VOCABULARY DEFINITION EXAMPLE
REFLECTION
The mirror image
produced by flipping a
figure over a line
PRIME
The term used to label
reflections.
Written as Aʹ
The reflection of
A(4,0) is Aʹ (-4,0)
You can use what you know about number lines and opposites to compare locations on the
coordinate plane. Consider the number line and coordinate plane below.
The number line shows that -4 and 4 are opposites.
The coordinate plane shows that the points (-4,0) and (4,0) are the
same distance from the y-axis in opposite directions. So, they are
reflected across the y-axis. Notice that the y-coordinate did not
change and that the x-coordinates are opposite.
When a point is flipped over the y-axis, the y-coordinate will stay the same and only the
x-coordinate in the ordered pair will change
When a point is flipped over the x-axis, the x-coordinatewill stay the same and only the
y-coordinate in the ordered pair will change.
AA
ʹ
A

4. Name the ordered pair that is a reflection of (-3,2) across the x-
axis.
To reflect across the x-axis, keep the same x-coordinate, -3, and take
the opposite of the y-coordiante. The opposite of +2 is -2.
So, (-3,2) reflected across the x-axis is located at (-3,-2)
Now you try!
Name the ordered pair that is a reflection of each point across the x-
axis.
1. (1,-4) (1,4) 2. (-2,5) (-2,-5) 3. (-3,-1) (-3,1)
Name the ordered pair that is a reflection of each point across the y-axis.
1. (1,-4) (-1,-4) 2. (-2,5) (2,5) 3. (-3,-1) (3,-1)
Refer to the diagram below to answer the following questions.
1. What is located at the reflection of (-3, -4) across the y-axis?
What are the coordinates of this location?
the gym; (3,-4)
2. What is located at the reflection of the science labs across the
x-axis? What are the coordinates of this location?
the art studio; (-3,2)
Refer to the map to answer the following questions.
1. What is located closest to the origin? The Clock
2. Liza is standing at (2,4). What is located at the
reflection of (2,4) across the x-axis? What are the
coordinates of this location?
The Wonder Wheel; (2,-4)
3. What is located at the reflection of (3,1) across the y-
axis? What are the coordinates of this location?
the Big Coaster; (-3, 1)
4. The Pipeline Plunge is reflected across the x-axis.
What are the coordinates of its new location?
(-1,-2)
A

5. Name _________________________________ Date _____________________
Mrs. Labuski / Mrs. Portsmore Period _______ Unit 11 Lesson 3 Reflections HW
OC 2-4
1. A triangle has vertices at point A with coordinates (2, 8), B (-5, -3), and C (9, 5). After the
triangle is reflected over the x-axis, what are the coordinates of its vertices?
Remember: When a point is flipped over the x-axis, the x-coordinate will stay the same
and only the y-coordinate in the ordered pair will change.
Write the new coordinates here: Aʹ__________ Bʹ____________
Cʹ____________
Plot the reflection and label the points.
A triangle has the coordinates of A(-2,1), B(2,4), C (4,2).
2. Which represents a reflection over the x-axis?
a.) Aʹ(-2,-1), Bʹ(2,-4), Cʹ(4, -2)
b.) Aʹ(2,-1), Bʹ(-2,4), Cʹ(-4,2)
c.) Aʹ(-2,-1), Bʹ(-2,-4), Cʹ(-4, -2)
d.) Aʹ(1,-2), Bʹ(4,2), Cʹ(2,4)
3. Which represents a reflection over the y-axis?
a.) Aʹ(-2,-1), Bʹ(2,-4), Cʹ(4, -2)
b.) Aʹ(2,-1), Bʹ(-2,4), Cʹ(-4, 2)
c.) Aʹ(-2,-1), Bʹ(-2,-4), Cʹ(-4, -2)
d.) Aʹ(1,-2), Bʹ(4,2), Cʹ(2,4)