Geometry

Question Analysis:
This question is about differentiating between rigid and non - rigid motions.
The main focus is on identifying the transformation that does not preserve the shape and size of a figure.

Key Concept Explanation:
Rigid motions (translations, rotations, reflections) preserve the shape and size of a figure.
Dilation changes the size of a figure and is not a rigid motion.

Step - by - Step Solution:
Analyze option A: Reflecting a triangle across the x - axis only changes its orientation, not its shape or size. So, it is a rigid motion.
Analyze option B: Rotating a square 180 degrees about its center changes the orientation but keeps the shape and size intact. So, it is a rigid motion.
Analyze option C: Dilating a circle by a scale factor of 2 changes its size. Since rigid motion preserves size, this is not a rigid motion.
Analyze option D: Tra...