January 15, 2016
H.W: Graph and label an image in quadrant 3 with at least 4 points.
Reflect the image over the x and y-axis. Be sure to label EACH point!
T.P: SWBAT Reflect over the x-axis
What will be the coordinates of (2.5,3) after a reflection across the y-axis? What
quadrant will the image be in?
January 15, 2016
Reflection over the x-axis means there is a
vertical transition (up and down). We can count
the units to help us graph the reflection.
Watch as I reflect over the x-axis.
(-5, 2) (0, 5) (5, 2)
January 15, 2016
Reflections Across the X-Axis
Ex 1: Graph Triangle ABC with coordinates A(2,3) B(3,5) C(1,4) and
its image after a reflection across the x-axis.
January 15, 2016
1 Assessment: What are the coordinates of (-5,-2) after a
reflection across the x-axis?
A
B
C
D
(5,2)
(-5,2)
(5,-2)
(-2,-5)
January 15, 2016
Classwork:
A: 1. What are the coordinates of (-3.5, 4) after a reflection across the x-axis?
2. State the coordinates of (9, -2 1/2) after a reflection over the x-axis.
B: Graph Triangle TRI with coordinates T(-4,0) R(-3,4) I(1,1) and its image after a
reflection across the x-axis. State the new coordinates of the image and explain
what happens to the coordinates of a figure when it is reflected across the x-axis.
C: Graph Triangle KLM with coordinates K(0,-4) L(2,3) M(-3,0) and its image after a
reflection across the x-axis. State the new coordinates of the image and explain
what happened to the coordinates of the original figure.
Enrichment: Create a conjecture about the following situation:
What happens to the coordinates of a point when the point is reflected across
the x-axis and then that image is reflected across the y-axis? Why?
January 15, 2016
Summary:
Discussion Question: What happens to the coordinates of a point when it is
reflected across the x-axis?
January 15, 2016