Definitions
Congruent
The same measure
Rigid transformations make what kind of figures?
congruent figures
What symmetry do you get from "folding" a shape
Reflection symmetry
Measurement of a straight angle?
180 degrees
What do you call the image of Point A?
A' (A prime)
Image
the result of a transformation
Name the 3 Rigid Transformations
Translation, Reflection, Rotation
What symmetry do you get from "spinning" a shape
Vertical Angle Theorem
Vertical angles are congruent.
Point C is the midpoint of segment AB. How does the length of AC compare to the length of CB?
They are congruent.
Midpoint
The point in the middle of a segment
What do you need to do a translation?
Directed Line Segment that shows direction and distance
What is the most symmetric shape?
Circle
Corresponding Angle Theorem
If two parallel lines are cut by a transversal, then corresponding angles are congruent
What do you get when you rotate a line around a center not on the line?
A parallel line
Regular Polygon
Shape with congruent sides and congruent angles
What do you need to do a reflection?
Line of Reflection
What shape has 180 degree rotation symmetry?
rectangle, square, regular hexagon, etc
Alternate Interior Angle Theorem
If two parallel lines are cut by a transversal, then alternate interior angles are congruent.
Point A is reflected across line m. How far away is Point A' from line m compared to Point A from line m?
Point A' is the same distance as point A away from line m.
Transversal
a line that passes through two lines in the same plane at two distinct points
What do you need to do a rotation?
Center of rotation, direction (clockwise or counterclockwise), Degree of rotation
How can you check for 180 degree rotation symmetry?
Spin the image 180 degree (half circle) and check if it looks the same.
Triangle Angle Sum Theorem
The three angle measures of any triangle always sum to 180 degrees.
Point A is reflected across line m. What can you say about segment AA' and line m?
They are perpendicular. Line m bisects segment AA'. Line m is the perpendicular bisector of AA'