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 a scale factor in dilations?

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 is the algebraic notation for a dilation with a scale factor of 2?

Back

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

Front

How do you find the coordinates of a dilated point?

Back

Multiply the original coordinates by the scale factor.

Front

What happens to the coordinates of a point (x, y) when dilated by a scale factor of 1/2?

Back

The new coordinates will be (1/2x, 1/2y).

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

If point A(4, 6) is dilated by a scale factor of 3, what are the new coordinates?

Back

A'(12, 18).

Front

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

Back

A negative scale factor reflects the figure across the center of dilation.