## Geometric Transformation (Reflecting a Triangle Over a Line)

In this geometric transformation triangle ABC is reflected over line MN. The initial triangle is green and its reflection is pink. You can move points M and N to change the position of the line of reflection (the red line). You can also move points A, B, or C to change the shape and the size of the green triangle.

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Activity Questions:

1) What is the relationship between the coordinates of the vertices of the initial triangle and those of the reflected triangle?

2) Now, move points M and N on the x-axis. How does the relationship between the green triangle and the pink triangle changes? Analyze the relationship between the coordinates of vertices A, B, C and those of points A', B', and C'.

3) Move points M and N so that the equation of the reflection line is y=x. What is the relationship between points A, B, C and vertices A', B', C'?

This Geometric Transformation Activity was created by Doina Popovici with GeoGebra.