Dilations

Front

What is a dilation in geometry?

Back

A dilation is a transformation that alters the size of a figure but not its shape, using a center point and a scale factor.

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

If the scale factor is greater than 1, what type of dilation occurs?

Back

An enlargement occurs when the scale factor is greater than 1.

Front

If the scale factor is less than 1, what type of dilation occurs?

Back

A reduction occurs when the scale factor is less than 1.

Front

What is the center of dilation?

Back

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

Front

How do you calculate the coordinates of a dilated point?

Back

To find the coordinates of a dilated point, multiply the original coordinates by the scale factor and then add the center of dilation coordinates.

Front

What happens to the angles of a figure during a dilation?

Back

The angles of a figure remain unchanged during a dilation.

Front

What is the effect of a dilation on the perimeter of a figure?

Back

The perimeter of a figure is multiplied by the scale factor during a dilation.

Front

What is the effect of a dilation on the area of a figure?

Back

The area of a figure is multiplied by the square of the scale factor during a dilation.

Front

Can a dilation be negative?

Back

No, a scale factor must be a positive number; a negative scale factor would reflect the figure as well as dilate it.