19 terms

Rules for transformations of geometric shapes on a coordinate plane

Transformation

To move a figure (or object).

Congruent

Figures that have the same size and shape. Figures that are reflected, rotated, or translated are congruent

Pre-Image (original/First)

The original object given. The FIRST or OLD figure.

Prime Notation

Symbolic representation given to images as a result of a transformation. If P is the original, P' (P prime) is the object after one transformation

Image (prime notation/Second/Copy)

A copy of the original: Example: A' is a copy of A

The SECOND or NEW figure.

The SECOND or NEW figure.

TranSLation

To SLide a figure.

The SLIDE does not change the size, orientation (the way it faces), or shape of the image.

The image is congruent to the original.

The SLIDE does not change the size, orientation (the way it faces), or shape of the image.

The image is congruent to the original.

Translation (slide)

(x, y) → (x + k, y + k)

K is a real (any) number

A translation can either effect only one value, for example the point can only slide up 2 units and only affect the y value (x, y+2) or the translation can affect both the x and y value, for example the point can slide up 2 units and to the left 3 units (x-3, y+2).

K is a real (any) number

A translation can either effect only one value, for example the point can only slide up 2 units and only affect the y value (x, y+2) or the translation can affect both the x and y value, for example the point can slide up 2 units and to the left 3 units (x-3, y+2).

ReFLection (Flip)

To FLip a figure.

When a figure is facing itself. The distance from the reflection line is equal in the pre-image (original) and the image (new) when a reflection has taken place.

The FLIP does not change the size, or shape of the image, but does change the orientation.

The image is congruent to the original.

When a figure is facing itself. The distance from the reflection line is equal in the pre-image (original) and the image (new) when a reflection has taken place.

The FLIP does not change the size, or shape of the image, but does change the orientation.

The image is congruent to the original.

Reflection over the x-axis

(x, y) → (x, - y)

x stays same; y changes sign

x stays same; y changes sign

Reflection over the y-axis

(x, y) → (- x, y)

x changes sign; y stays the same

x changes sign; y stays the same

RoTAion (Turn Around)

To Turn a figure Around a point.

We will use the origin (0, 0) as our point of rotation.

The TURN AROUND does not change the size, or shape of the image, but does change the orientation.

The image is congruent to the original.

We will use the origin (0, 0) as our point of rotation.

The TURN AROUND does not change the size, or shape of the image, but does change the orientation.

The image is congruent to the original.

Rotation 90° about the origin

(x, y) → (y, - x)

x change signs; y stays the same and then SWITCH the x and y values

x change signs; y stays the same and then SWITCH the x and y values

Rotation 180° about the origin

(x, y) → (- x, - y)

x change signs; y change signs

Here they both change their signs, it is like a double reflection.

x change signs; y change signs

Here they both change their signs, it is like a double reflection.

Rotation 270° about the origin

(x, y) → (- y, x)

x stays the same; y changes it's sign, and then SWITCH the x and y values

x stays the same; y changes it's sign, and then SWITCH the x and y values

Scale Factor

A scale (k) written as a ratio in simplest form. The scale factor is a number used to multiply the lengths of a figure to stretch (enlarge) or shrink (reduce) it to a similar image.

Always multiply by the Scale Factor when preforming a Dilation.

To find the scale factor of 2 objects use Second/First.

S ÷ F

Always multiply by the Scale Factor when preforming a Dilation.

To find the scale factor of 2 objects use Second/First.

S ÷ F

Enlargement

A dilation in which the image is larger than the pre-image.

Reduction

A dilation in which the image is smaller that the pre-image.

Dilation (Size Change)

Enlargement or reduction of the original figure.

The size change of course changes the size but the shape and orientation stay the same.

The image is no longer congruent but it is similar to the original.

The size change of course changes the size but the shape and orientation stay the same.

The image is no longer congruent but it is similar to the original.

Dilation (use Scale Factor)

(x, y) → (kx, ky)

where k is a real number

Here you multiply the original x and y value by the scale factor.

where k is a real number

Here you multiply the original x and y value by the scale factor.