Congruence and Transformations Answers

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A teacher asks students to determine the accuracy of this statement.A reflection over the x-axis and then over the y-axis results in the same transformation as a 180 rotation about the origin of the original figure.Kwame’s explanation of the accuracy of the statement is shown below.Step 1: Choose the vertices of a pre-image: (1, 2), (1, 4), (2, 3). Step 2: Reflect the pre-image over the x-axis: (1, –2), (1, –4), (2, –3).Step 3: Reflect the figure from step 2 over the y-axis: (–1, 2), (–1, 4), (–2, 3).Step 4: Rotate the pre-image 180: (–1, –2), (–1, –4), (–2, –3).Step 5: Compare the reflected figure to the rotated figure. The vertices are not located in the same place, therefore the statement made by the teacher is inaccurate.Which best explains Kwame’s solution?

Question illustration
A
Kwame’s explanation and solution are incorrect. He reflected the image over the y-axis in step 2 and the x-axis in step 3, instead of the reverse.
B
Kwame’s explanation and solution are incorrect. He reflected the pre-image at step 3, rather than the figure from step 2.
C
Kwame’s explanation and solution are incorrect. When reflecting over the x- and y-axes, he negated the incorrect coordinate in the ordered pair.
D
Kwame’s explanation and solution are incorrect. The coordinates of the rotated figure should be switched and negated, not just negated.
3

Triangle ABC is rotated 180º using the origin as the center of rotation.Which sequence of transformations will produce the same result?

Question illustration
A
a translation up 4 and then a reflection over the y-axis
B
a translation up 4 and then a translation right 6
C
a reflection over the x-axis and then a reflection over the y-axis
D
a translation right 6 and then a reflection over the x-axis
5

The vertices A(–2, –1), B(–3, 2), C(–1, 3), and D(0, 0) form a parallelogram. The vertices A’(–1, –2), B’(2, –3), C’(3, –1), and D’(0, 0) are the image of the parallelogram after a sequence of transformations. Which sequence of transformations could produce the image from the pre-image?

A
a reflection over the x-axis and then a reflection over the y-axis
B
a reflection over the y-axis and then a 90 clockwise rotation about the origin
Option B
C
a 90 clockwise rotation about the origin and then a reflection over the y-axis
Option C
D
a 90 counterclockwise rotation about the origin and then a reflection over the x-axis
Option D
7

Figure X is translated down 5 and then reflected over the y-axis, forming figure Y. Which sequence of transformations results in the same transformation?

Question illustration
A
a translation left 5 units and then a reflection over the x-axis
B
a translation left 5 units and then a translation down 5 units
C
a 180 rotation using the origin as the center of rotation
Option C
D
a reflection over the y-axis and then a translation down 5 units
8

Triangle MNO is reflected over the x-axis and then translated up 4 and right 3. How can the transformation be amended such that the translation can occur before the reflection and have the image remain in the same position?

Question illustration
A
Translate the pre-image down 4 and right 3 and then reflect the figure over the x-axis.
B
Translate the pre-image up 3 and right 4 and then reflect the figure over the x-axis.
C
Translate the pre-image up 4 and left 3 and then reflect the figure over the y-axis.
D
Translate the pre-image down 3 and right 4 and then reflect the figure over the x-axis.
9

Triangle MNO is rotated 180 using the origin as the center of rotation. Which sequences of transformations will produce the same results? Check all that apply.

Question illustration
A
a reflection over the x-axis and then a reflection over the y-axis
B
a reflection over the y-axis and then a reflection over the x-axis
C
a 90 clockwise rotation about the origin and then a 90 counterclockwise rotation about the origin
Option C
D
a translation 6 units right and then a reflection over the x-axis
E
a translation 4 units down and then a reflection over the y-axis
10

Chareese reflects figure RSUT over the y-axis and then rotates the reflected figure 180 about the origin, resulting in figure A. She states that . Which best describes the accuracy of her congruency statement?

Question illustration
A
Accurate. A reflection will change the direction the vertices trace around the figure. A rotation preserves the change.
B
Accurate. A reflection preserves the direction the vertices trace around the figure. A rotation changes that direction.
C
Inaccurate. The correct congruency statement is .
Option C
D
Inaccurate. The correct congruency statement is .
Option D

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