Answer:
16mm
Step-by-step explanation:
Just do 40 * 2/5 = 80/5 = 16mm
I don't know which quadrent the rectangle started in because there is no image, but it should be easy for you to apply the steps. You know that it is being reflected over the x-axis, this means that x will stay the same, and y will be negative. The x axis is the horizontal one, so if you look at where it is, you can either visualize, or use tracing paper to determine where it will end up.
Erik's error was that he forgot the 2 that was in the side of 3/4.
AE is perpendicular to these lines i hope this helped you have a good rest of the day