Geometry

Question Analysis:
This question involves identifying examples of rigid motion within the topic of geometry.
The main focus is on differentiating between transformations that are rigid motions and those that are not.

Key Concept Explanation:
Rigid motion, also known as isometry, preserves the shape and size of a figure.
This means distances between points and angles within the figure remain the same.
Rotations, translations, and reflections are types of rigid motion.

Step - by - Step Solution:
Analyze option A: Shrinking a triangle by half changes its size, so it is not a rigid motion.
Analyze option B: Rotating a square 90 degrees counterclockwise only changes its orientation.
The shape and size remain the same, making it a rigid motion.
Analyze option C: Stretching a rectangle horizontally changes its dimensions, so it is not a rigid motion.
Analyze option D: Distorting a hexagon changes its shape, so it...