Student activity · Grades 8–10 · about 25 minutes

Transformations Worksheet: Translate, Rotate & Reflect

Goal: Apply translations, rotations and reflections to a triangle on the coordinate plane, write the coordinate rule for each, and see which transformations keep the size the same.

Tool: Transformation playground at geometrylab.net/tools/transformations/ · Connects to Common Core 8.G.A.3, HSG-CO.A.5

What to do

  1. Open the transformation playground. The original triangle is A(−2, −1), B(2, −1), C(0, 2), with an area of 6 square units.
  2. Press “Translate”, set “Horizontal translation” to 2 and “Vertical translation” to 1, and record A′, B′, C′ and the new area.
  3. Press “Rotate” and record the results for “Rotation angle (°)” = 90, then 180.
  4. Record the results for “Reflect over x-axis” and “Reflect over y-axis”. Then press “Scale from origin”, set “Scale factor” to 2, and record.

Record your results

SettingA′B′C′New area
Translate by (2, 1)
Rotate 90°
Rotate 180°
Reflect over x-axis
Reflect over y-axis
Scale factor 2

Questions

  1. Write the coordinate rule for the translation you used. Did the area change?

  2. Look at the 90° rotation. Find the rule that turns each original point into its image.

  3. Compare the 180° rotation with two reflections in a row: first over the x-axis, then over the y-axis. What do you find?

  4. Which transformations kept the area at 6 square units? Which one changed it, and by what factor?

  5. Predict where C(0, 2) lands after a 270° counterclockwise rotation. Then set the rotation angle to 270 to check.

  6. In the original triangle, going A → B → C runs counterclockwise. Which transformations in your table reverse this to clockwise?

Free from Geometry Lab · geometrylab.net · 8.G.A.3: Describe the effect of dilations, translations, rotations and reflections on two-dimensional figures using coordinates. HSG-CO.A.5: Given a geometric figure and a rotation, reflection or translation, draw the transformed figure.

Teaching with this? Find the answer key and more activities on the Geometry Lab for teachers page.