Self-Quiz: What's That Isometry?


Below, find a triangle before (blue) and after (gold) an isometry moves it. Your job is to decide what kind of isometry it is: Translation, Rotation, Reflection, or Glide Reflection. Tips:
  • For a new isometry, press Shuffle.
  • To check your answer, click Reveal Answer.
  • You can give the image A'B'C' more or less freedom by adjusting Leash Length--but if ABC is far from the middle, or Leash Length is too great, A'B'C' may be off-screen.
Optional: To make this task harder, after you have a prediction of the type of isometry, try to also predict (or construct!) additional details, such as vectors of translation, centers and angles of rotation, and lines of reflection. To make this task easier, move points A, B, and/or C. Sometimes there's a specific "before" point that helps you more than the default A, B, C; also, if you move a point in small circles and see which direction its image circles, you can narrow down the choices.