Dilations Warm-Up 9.11.19

Front

What is a dilation in geometry?

Back

A dilation is a transformation that alters the size of a figure but preserves its shape and the proportions of its dimensions.

Front

What does it mean for a transformation to preserve congruence?

Back

A transformation preserves congruence if the original figure and the transformed figure are identical in shape and size.

Front

Which transformations preserve congruence?

Back

Rotations, reflections, and translations preserve congruence.

Front

What is the scale factor in a dilation?

Back

The scale factor is a number that describes how much a figure is enlarged or reduced during a dilation.

Front

How do you write the algebraic notation for a dilation with a scale factor of 1/2?

Back

(x, y) goes to (1/2x, 1/2y).

Front

How do you write the algebraic notation for a dilation with a scale factor of 3?

Back

(x, y) goes to (3x, 3y).

Front

If a point B (4,9) is dilated with a scale factor of 2, what are the coordinates of the image?

Back

(8, 18).

Front

What is the effect of a scale factor greater than 1 in a dilation?

Back

A scale factor greater than 1 enlarges the figure.

Front

What is the effect of a scale factor between 0 and 1 in a dilation?

Back

A scale factor between 0 and 1 reduces the figure.

Front

What is the center of dilation?

Back

The center of dilation is the fixed point in the plane about which all points are expanded or contracted.