Geo 4.5 Dilations

Front

What is a dilation in geometry?

Back

A dilation is a transformation that produces an image that is the same shape as the original, but is a different size. It is defined by a center of dilation and a scale factor.

Front

What does the scale factor in a dilation represent?

Back

The scale factor is a number that describes how much the figure is enlarged or reduced during a dilation. A scale factor greater than 1 enlarges the figure, while a scale factor between 0 and 1 reduces it.

Front

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

Back

(-5, -3)

Front

What happens to the coordinates of a rectangle with vertices (2, 2), (2, -2), (-2, -2), and (-2, 2) when dilated by a scale factor of 2?

Back

(4, 4), (4, -4), (-4, -4), (-4, 4)

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 during a dilation.

Front

What does a scale factor of less than 1 indicate?

Back

It indicates that the image will be a reduction of the pre-image.

Front

What is the result of a dilation with a scale factor of 1?

Back

The image will be the same size as the pre-image.

Front

If a triangle is dilated by a scale factor of 1/4, what can be said about the new image?

Back

The new image will be smaller than the original triangle.

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

How do you find the coordinates of a dilated point?

Back

Multiply each coordinate of the original point by the scale factor.