Exploring ReFLections (Flip)
Below is an example of a preimage (on the left) reflected over the y axis to create an image (on the right). The dotted line is called the line of symmetry. Drag it around to see what happens, then answer the questions below.
Is the image congruent to the preimage?
Drag the line of symmetry so that the equation is x = 0 (click box in upper left corner to see the equation), which axis is the line of symmetry overlapping?
Now look at the (x,y) coordinates for the image and the preimage when the line of symmetry is the y axis (equation x=0), which coordinates are the same for both figures?
When the line of symmetry is the y axis, we say that the preimage is reflected over the y axis, and the y coordinates stay the same. What do you notice happened to the x coordinates?
What happens when the line of symmetry for the reflection is the x axis?
Now drag the line of symmetry so that it overlaps the x axis. The equation for the line should be y = 0. What do you notice about the coordinates of the preimage and the image?