Question

The shaded octagon is transformed to the unshaded octagon in the coordinate plane below.

On a coordinate plane, a shaded octagon is reflected across a diagonal line to form the unshaded octagon.

Which statement about the transformation is true?
The unshaded octagon is a reflection because it is a flip over a diagonal line.
The unshaded octagon is a dilation because it is smaller than the shaded octagon.
The unshaded octagon is a horizontal translation because it is directly to the left of the shaded octagon.
The unshaded octagon is a vertical translation because it is directly under the shaded octagon.

Answer 1

The first statement is true: the unshaded octagon is a reflection — it is a flip across the diagonal line. The image is the same size and shape but mirrored across that line (so it's not a dilation or a pure horizontal/vertical translation).