Video Transcript
Which of the following represents a
rotation of the shaded figure?
Let’s begin by recalling that a
rotation is the transformation that turns a shape in a circular motion about a
point. If you find it difficult to
visualize transformations or even rotations, it can be helpful to use tracing
paper. Put the tracing paper over the
shape and trace over the outline. As we’re thinking about a rotation,
it can be helpful to put our pencil point anywhere on the tracing paper and turn it
and then see what happens. Out of the options that we’re
given, the option (C) produces a rotation.
Just like in the sketch, if we
placed our pencil point with the tracing paper here and rotated the shaded figure 90
degrees clockwise, then we’d end up with the following image. We could’ve also rotated 270
degrees counterclockwise and achieved the same image. Therefore, option (C) is the
correct answer. But let’s have a quick look at the
other options.
Option (A) has two shapes which
look like a mirror image of each other. Therefore, this is a
reflection. The line of reflection would appear
halfway between these two shapes. But it’s not a rotation, so it’s
not the answer. In option (B), the image is four
places to the right of the original shaded figure, indicating that this is a
translation but not a rotation. In option (D), this shaded figure
and the unshaded figure are not congruent or similar. Therefore, this doesn’t represent
any transformation and certainly not a rotation. So, we can give the answer as
option (C).
