Transformations (TEKS 8.3C, 8.10C, 8.10D)

Front

What is a transformation in geometry?

Back

A transformation is a change in the position, size, or shape of a figure. Common types include translations, rotations, reflections, and dilations.

Front

What is dilation in geometry?

Back

Dilation is a transformation that changes the size of a figure but not its shape. It is defined by a center of dilation and a scale factor.

Front

What is the scale factor in dilation?

Back

The scale factor is a number that describes how much a 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

What is the rule for dilating a point (x, y) by a scale factor of k?

Back

The rule for dilating a point (x, y) by a scale factor of k is (x, y) --> (kx, ky).

Front

What happens to the coordinates of a figure when it is reflected across the y-axis?

Back

When a figure is reflected across the y-axis, the x-coordinates of the points change sign. The rule is (x, y) --> (-x, y).

Front

What is the effect of a reflection across the x-axis on the coordinates of a point?

Back

A reflection across the x-axis changes the sign of the y-coordinate. The rule is (x, y) --> (x, -y).

Front

What is a translation in geometry?

Back

A translation is a transformation that moves every point of a figure the same distance in the same direction.

Front

What is the rule for translating a point (x, y) by (a, b)?

Back

The rule for translating a point (x, y) by (a, b) is (x, y) --> (x + a, y + b).

Front

What is the perimeter of a figure after dilation by a scale factor of k?

Back

The perimeter of a figure after dilation by a scale factor of k is k times the original perimeter.

Front

If a figure is dilated by a scale factor of 2, what happens to its area?

Back

If a figure is dilated by a scale factor of k, the area of the figure is multiplied by k^2. So, if k = 2, the area is multiplied by 4.