Question

Which of the following is not a rigid motion transformation?

A. Translation
B. Stretch
C. Rotation
D. Reflection

Answer 1

B. Stretch

Explanation:

A rigid motion, also called an isometry, is a transformation that maintains congruence. This means all of the image angles will be congruent to the corresponding pre-image angles, and all of the image sides will be congruent to the pre-image sides.

In a translation, the figure is slid. This does not change angle measure or side length; this is a rigid motion.

In a rotation, the figure is turned. This does not change angle measure or side length; this is a rigid motion.

In a reflection, a mirror image of the figure is created. This does not change angle measure or side length; this is a rigid motion.

In a stretch, a figure is enlarged by a scale factor. This changes side length; this is not a rigid motion.

Answer 2

B) Stretch

Rigid motion means the pre-image and the image has the same size and shape. All translations, rotations and reflections preserve the original size and shape.