PA Vocabulary Transformational Geometry

Front

Area

Back

The measurement attribute that describes the number of square units a figure or region covers.

Front

Center of dilation

Back

A coordinate point that serves as the focal point for generating a dilation. (usually the origin).

Front

Circumference

Back

The distance around a circle.

Front

Congruent

Back

Having exactly the same size and same shape.

Front

Dilation

Back

A transformation in which an image is enlarged or reduced, depending on the scale factor, proportional to the Preimage.

Rule: (x,y)→(kx,ky).

Front

Perimeter

Back

The distance around the outer edge of a figure.

Front

Positive rational numbers

Back

The set of numbers that can be expressed as a fraction, where a and b are counting (natural) numbers.

Front

Rotation

Back

A transformation described as a turn of a figure around a designated point.

Rules:

90° CW or 270° CCW (x,y)→(y,-x),

180° CW or CCW (x,y)→(-x,-y),

90° CCW or 270° CW (x,y)→(-y,x).

Front

Reflection

Back

A transformation described as a flip or a mirror image of the original figure.

Rules:

Over x-axis (x,y)→(x,-y),

Over y-axis (x,y)→(-x,y),

Over y= x (x,y)→(y,x),

Over y= -x (x,y)→(-y,-x).

Front

Scale factor

Back

The number a figure is dilated by, represented by k.

Equal to 'new/old' or 'Image/Pre-Image'.