Unit: TransformationsName Answer Key

Student Handout 3 Date

REFLECTIONS ON THE COORDINATE PLANE

flips a figure over a line ofre f lection in

REFLECTIONSorder to create a mirror image.

Each reflected point of the figure should be the same distance from the

line of reflection on the opposite side.

6Highlight and identify the line of x-axis

reflection in each of the examples:

*In the alg. representations below ) students usuallyneed reminders that a negative sign also means

«the opposite') of something. It doesn't necessarily

mean that the value becomes negative.

Y-axis

1. Reflect the figure shown over the y-axis. Record thecoordinates of the pre-image and image.

PRE-IMAGE IMAGE

W'(-2J 6)

Describe any patterns found inthe ordered pairs:

The x-values became theiropposite and the y-valuesstayed the same.

How can we represent this algebraically Q

2. Reflect the figure shown over the x-axis. Record the

coordinates of the pre-image and image.anuunanuunannøa

PRE-IMAGE IMAGEthe Describe

ordered any

pairs:patterns found in

The y-values became theiropposite and the x-valuesstayed the same.

How can we represent this algebraically Q

3. Reflect triangle PC)R over the y-axis, Then, describe what happened to each of the

coordinates.The y-values stayed fhe sarne andthe x-values became their opposite.

4. Reflect your new triangle P'Q'R) over the x-axis. Then,describe what happened to each of the coordinates.

The x-values stayed the same andthe y-values became their opposite.

5. Bella thinks that the transformation belowrepresents a translation. Is she correct Q Whyor why not o

No; it cannot be a translation because theorientation of the vertices has changed. If is areflection.

7. Use what you've learned to show where thefollowing points would be after the given

6. Use the chart to compare and contrasttranslations and reflections.

SIMILARITIES

Both create animage that iscongruent tothe pre-image.

DIFFERENCES

A translationpreserves the

orientation of thefigure and itsvertices but areflection does not.

PRE-IMAGE

cc -q)

-Il)

12)

REFLECTION

OVER I-ms

(10, q)

(7, -12)

REFLECTION

OVER I-ms

(- 10)-q)

12)

8. Write in your own words what happens to thecoordinates in a figure when the followingoccur:

Reflection over the x-axis:

The y-values become their opposite and thex-values stay the same.

Reflection overhhe y-axis:The x-values become their opposite and they-values stay the same.