Question

part a: explain in complete sentences why a reflection is a type of rigid motion.
part b: name another rigid motion.

Explanation:

Part A: A rigid motion preserves the size and shape of a figure, meaning all side lengths and angle measures remain unchanged after the transformation. A reflection flips a figure over a line, but it does not alter the length of any sides or the measure of any angles in the figure; it only changes the figure's orientation and position. Since it maintains the figure's congruence, it qualifies as a rigid motion.
Part B: Rigid motions include transformations that preserve congruence, and translation is a common example of this type of transformation.

Answer:

Part A: A reflection is a rigid motion because it preserves the size and shape of the original figure, keeping all side lengths and angle measures identical to the pre-image, only flipping the figure across a line without altering its congruence.
Part B: Translation (or rotation, either is acceptable; translation is used here as the example)