If a figure has been dilated by a scale factor of [tex]\frac{1}{3}[/tex], which transformation could be used to prove the figures are similar using the AA similarity postulate?

A. A translation because it can map one angle onto another since dilations preserve angle measures of triangles.

B. A rotation because it can change the orientation of a figure since dilations do not preserve orientation.

C. A reflection because it can change the orientation of a figure since dilations do not preserve orientation.



Answer :

To determine which transformation could be used to prove that figures are similar using the AA (Angle-Angle) similarity postulate, it's important to understand the properties of each transformation in the context of similarity and how dilations affect a figure.

1. Translation:
- A translation moves every point of a figure the same distance in the same direction.
- Translations preserve the shape and size of a figure and do not change angle measures.
- Since dilations preserve angle measures and a translation can directly map corresponding angles of two figures, this transformation helps in showing that the corresponding angles of the two figures are congruent.

2. Rotation:
- A rotation moves a figure around a fixed point without changing the shape or size of the figure.
- Rotations also preserve angle measures but change the orientation of the figure.
- Since dilations preserve shapes and angles but not sizes, the corresponding angles in a rotated figure will still be congruent to the original figure. However, rotations would not typically be used to directly show similarity by the AA postulate since the main point here is to consider angle congruence without needing to alter orientation.

3. Reflection:
- A reflection flips a figure over a line, creating a mirror image.
- Reflections preserve angles but change orientation.
- Similar to rotations, reflections maintain angle congruence but are not directly focused on mapping angles without altering the figure’s orientation.

Since the AA similarity postulate relies on establishing that two sets of corresponding angles are equal, and given that dilations preserve these angles:

- Translation is the most appropriate transformation for demonstrating similarity using the AA postulate in this context because it can map one angle to another directly, thereby helping to establish that the corresponding angles are congruent without altering the shape or orientation.

Therefore, the correct answer is:
- A translation because it can map one angle onto another since dilations preserve angle measures of triangles.

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