FLASHCARDIZZ: 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 of dilation 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.

Front

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

Back

A reduction occurs.

Front

What happens to the coordinates of a point (x, y) when it is dilated by a scale factor k?

Back

The new coordinates become (kx, ky).

Front

What is the center of dilation?

Back

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

Front

How do you determine the scale factor from two points before and after dilation?

Back

Divide the distance of the image point from the center of dilation by the distance of the original point from the center.

Front

What is the effect of a negative scale factor in dilation?

Back

A negative scale factor reflects the figure across the center of dilation and changes its size.

Front

What are the coordinates of point A(3,3) after dilation by a scale factor of 3?

Back

A'(9,9).

Front

What are the coordinates of point B(6,6) after dilation by a scale factor of 3?

Back

B'(18,18).