Defining Reflections


Move points A, B, and C to change the shape of the triangle. Move points P and Q to move the line of reflection. Click the boxes to show segment lengths and AA', BB' and CC'.

Question 1

Select the boxes for AA', BB' and CC'. What do you about the slope of these lines and the line of reflection, PQ?

Question 2

Select the box for Lengths. What do you notice? What is the relationship between the line of reflection and AA', BB' and CC'?

Question 3

Move point P to point A. How does this affect A'?

Question 4

What is true about the line of reflection and line segments AA', BB' and CC'?

Check all that apply

Question 5

Write a precise definition for a rotation, using the following words or objects:

  • Line of reflection PQ
  • Point A, not on the line PQ
  • Point B, on the line PQ
  • Line segment AA'
  • Perpendicular bisector

Question 6

Which of the following are properties of the reflected triangle A'B'C'?

Check all that apply