7.1 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 the ratio of a length of the new figure to the corresponding length on the original figure.

Front

How do you calculate the coordinates of a point after dilation?

Back

To find the coordinates of a point after dilation, multiply the original coordinates by the scale factor.

Front

What happens to a figure when the scale factor is greater than 1?

Back

When the scale factor is greater than 1, the figure is enlarged.

Front

What happens to a figure when the scale factor is between 0 and 1?

Back

When the scale factor is between 0 and 1, the figure is reduced.

Front

If point B (-10, -6) is dilated with a scale factor of 1/2, what are the new coordinates?

Back

The new coordinates are (-5, -3).

Front

If point A (8, 12) is dilated to (2, 3), what is the scale factor?

Back

The scale factor is 1/4.

Front

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

Back

The new coordinates are (9, 9).

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.

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 in addition to resizing it.