Final answer:
When you adjust your rearview mirror, you should see the entire rear window to maximize visibility of the area behind your vehicle, which enhances driving safety by minimizing blind spots.
Step-by-step explanation:
When adjusting your rearview mirror, the goal is to see as much of the scene behind you as possible to maintain awareness of your surroundings while driving. The mirror should be positioned so that you can see the entire rear window, which generally means you should see a bit of the inside of your car at the edges, typically the rear headrests, as a reference point. This is important for safety to ensure a clear view of the traffic and to minimize blind spots. The reference to the size of the mirror mentioned, "the mirror should be half your size" and its top edge at "the level of your eyes", corresponds to the visibility you should aim for when you look into the rearview mirror. While no exact specifications are provided for car mirrors, this may imply the conceptual understanding that the mirror should provide a full view. As per the theory of mirrors, Figure 25.48 illustrates how two mirrors can be used to direct light as in a headlight, and it can be inferred that the rearview mirror also helps in making driving decisions by showing the traffic that is behind the vehicle without the need for a real image projected on a screen. Hence, positioning is crucial and should not be neglected.