This doesn't change during rigid transformations.
What is the size?
The word that describes translating.
What is sliding?
The word that describes rotating
What is turning?
This word is another way of saying reflecting
What is flipping?
A triangle has this many degrees
What is 180?
These are the types of transformations that do not change the size.
What are reflections, translations, and rotations?
Adding a positive number to the x-coordinate moves a figure in this direction.
What is to the right?
Making both coordinates negative rotates the figure this many degrees.
What is 180o (clockwise or counterclockwise)?
The figure has been reflected over this line.

What is the x-axis?
Angles 4 & 6, and angles 3 & 5 are this.

What are alternate interior angles?
The picture below shows this type of transformation.

What is rotating?
This is the image coordinate pair when the preimage (1, 6) is translated to the left 3 and down 1.
What is (-2, 5)?
The segment below has been rotated 90o in this direction. (green to purple)

What is counter clockwise?
This is the coordinate A' after the figure below has been reflected over the given line.

What is (6, 1)?
Angles 1 & 7, and angles 2 & 8 are this.

What are alternate exterior angles?
This notation(symbol) is how we differentiate the preimage from the image.
What is prime (small tick mark)?
This mathematical operation happens to the x coordinate if a figure translates to the left.
What is subtracting?
This is the coordinate M' after the figure below is rotated 180o clockwise.

What is (-6, -6)?
The given graph depicts this rigid transformation over this line.
What is a reflection in the y-axis?
Angles 2 & 6, and angles 3 & 7, and angles 1 & 5, and angles 4 & 8 are this.

What are corresponding angles?
This color figure is the image in the following reflection:

What is the blue figure?
The shapes are translated in this direction these many units. (green to purple)

What is left two units, up two units?
This clockwise rotation is the same as rotating 90o counterclockwise.
What is 270o clockwise?
The distance between the pre-image and the line of reflection, and the image and the line of reflection, are always this.
What is the same?
Angles 1 & 3, angles 2 & 4, angles 6 & 8, and angles 5 & 7 are these.

What are vertical angles?
This rule describes rotating 270o clockwise.
What is (x,y) to (-y, x)?
The graph depicts this rigid transformation this number of units in these directions.
What is a translation 1 unit right 2 units down?
The measure of the angle of rotation of ABCD about the origin. 
What is 270 degrees CCW or 90 degrees CW
Alternate interior angles, alternate exterior angles, corresponding angles, and vertical angles are all this.
What is congruent?
This is the verbal description of the following rule: (x, y) to (y, -x)
What is rotating 270o counterclockwise?
or
What is rotating 90o clockwise?
The given graph depicts this rigid transformation this number of degrees in this direction. (grey to red)
What is a 90-degree clockwise rotaition?