Lesson 24 — Activity 1: Creating Reflections of Geometric Figures
Completion requirements
Lesson 24 — Activity 1:
Creating Reflections of Geometric Figures
Lesson 24 — Activity 1:
Creating Reflections of Geometric Figures
Have you ever looked at your reflection in the mirror and winked at yourself? Did you notice that the image appears to wink with the opposite eye? That is because the mirror image is flipped (reversed) compared to the original! The image is
similar but opposite. This is known as a reflection.
Have you ever looked at your reflection in the mirror and winked at yourself? Did you notice that the image appears to wink with the opposite eye? That is because the mirror image is flipped (reversed) compared to the original! The image is similar but opposite. This is known as a reflection.
When a shape is given a mirror image based on a line of reflection, it is called a reflection or a flip. The directions for a reflection must always include the reflection line (also called the mirror line or the snap line).
The Line of Reflection or Mirror Line
When a shape is given a mirror image based on a line of reflection, it is called a reflection or a flip. The directions for a reflection must always include the reflection line (also called the mirror line or the snap line).
The Line of Reflection or Mirror Line
Mirror lines can be in any direction. Imagine turning the photo at the top in different directions. The reflected image is always the same size, it just faces the other way!
For the reflection to work, all corners (vertices) of the shape's image must be an equal distance from the reflection line but on the other side from the original. The line of reflection is easily shown on the coordinate grid.
When the shape is located directly on either side of the reflection line so that both shapes match exactly, it is described as symmetrical. This is defined as symmetry, because the two figures are identical.
The two figures on either side of the reflection line match exactly, so they are symmetrical.
If you drew an imaginary line down your body from the top of your head to the bottom of your feet, then you would have two symmetrical shapes. The left side of your body matches the right side of your body!
Let's look at an example below. The reflection figure (blue square) has been reflected across the Line of Reflection and becomes the new figure (red square). It has been reflected one square to the right on the
x axis
.
Let's look at another example. The reflection figure below (blue parallelogram) has been reflected across the Line of Reflection and becomes the new figure (red parallelogram). It has been reflected two squares down on the
y axis
.
