Transformations
One of the rigid transformations is reflection. When a figure is reflected across some line, it maps to the very same shape but inverted as if the line was a mirror.
Right between figures W and W' the y-axis separates two identical images as if the y-axis was a mirror, thus:
Figure W was reflected over the y-axis to create figure W'
A Dilation from the origin maps an object to another such that its vertices are all multiplied by a common factor (scale factor).
For example, the upper-right vertex of W' is located at (2-2). The upper-right vertex of W'' is at (4,-4). The scale factor is 2.
The bottom-left vertex of W' is at (4,-4) and the bottom-left vertex of W'' is at (8,-8). We find the same scale factor of 2. If we tested all of the vertices, we'll obtain the same scale factor of 2, thus:
Figure W' was dilated by a scale factor of 2 from the origin to create figure W''
