Reflection and Congruency in Geometry

Mr. Taylor introduces reflection as a type of transformation, explaining it as a mirror image and a rigid transformation known as isometry. The video covers learning objectives, key vocabulary like orientation and congruency, and the properties of reflection, including the line of reflection and distance. An activity involves reflecting a triangle across the x and y axes, analyzing the results, and ensuring congruency and equal distances from the line of reflection. The video concludes with a summary of the reflection activity.

What type of transformation is a reflection?

• A transformation that rotates a figure

• A transformation that slides a figure

• A transformation that flips a figure across a line

• A transformation that enlarges a figure

What is the term for the arrangement of points after a transformation?

• Reflection

• Symmetry

• Orientation

• Congruency

What does congruency mean in the context of transformations?

• Having different shapes and sizes

• Being able to rotate freely

• Having the same shape, size, and measure

• Being able to slide in any direction

What is the line called that a figure flips across during a reflection?

• Axis of symmetry

• Line of congruency

• Line of reflection

• Line of orientation

In a reflection, how are the distances of each point and its image from the line of reflection related?

• They are different

• They are equal

• They are proportional

• They are unrelated

What is the first step in reflecting a triangle across the x-axis?

• Rotate the triangle

• Fold the paper along the x-axis

• Slide the triangle

• Enlarge the triangle

After reflecting a triangle across the x-axis, what should you do next?

• Rotate it 90 degrees

• Reflect it across the y-axis

• Enlarge it by a factor of 2

• Slide it to the right

How do you find the perpendicular distance from a point to the line of reflection?

• Measure the horizontal distance

• Measure the vertical distance

• Measure the shortest distance

• Measure the diagonal distance

What do you notice about the distances from the pre-image and image to the line of reflection?

• They are unrelated

• They are equal

• They are different

• They are proportional

When reflecting across the y-axis, how does the image compare to the pre-image?

• The image is rotated

• The image is flipped

• The image is translated

• The image is enlarged