Unit 1: Transformations in the Coordinate Plane

Question 1

Transformation

Answer 1

A change in the position, size, or shape of a figure. Includes translations, reflections, rotations, and dilations.

Question 2

Preimage

Answer 2

The original figure before a transformation is applied.

Question 3

Image

Answer 3

The figure after the transformation.

Question 4

Isometry (Rigid Motion)

Answer 4

A transformation that preserves distance and angle measure (shape and size stay the same).
Examples: Translation, reflection, rotation

Question 5

Translation

Answer 5

A “slide” — moves every point of a figure the same distance in the same direction.

Question 6

Reflection

Answer 6

A “flip” — a mirror image over a line (called the line of reflection).

Question 7

Rotation

Answer 7

A “turn” — rotates a figure around a fixed point (called the center of rotation) by a certain angle.

Question 8

Dilation

Answer 8

A transformation that changes the size of a figure but not its shape. It uses a scale factor and a center of dilation.
• Enlargement: scale factor > 1
• Reduction: scale factor between 0 and 1

Question 9

Scale Factor

Answer 9

The ratio of the image’s size to the preimage’s size in a dilation.

Question 10

Center of Dilation

Answer 10

The fixed point in a dilation from which all points are expanded or contracted.

Question 11

Congruent figures

Answer 11

Figures that are the same size and shape. Rigid motions produce congruent figures.

Question 12

Similar figures

Answer 12

Figures that have the same shape but not necessarily the same size. Dilations produce similar figures.

Question 13

Line of Symmetry

Answer 13

A line that divides a figure into two mirror-image halves.

Question 14

Rotational Symmetry

Answer 14

A figure has this if it can be rotated (less than 360°) and still look the same.

Question 15

Composition of Tansformations

Answer 15

Applying two or more transformations in a sequence