The human eye has a lot in common with a pinhole camera, being essentially a small box with a hole in the front (the pupil) and "film" at the back (the retina). The distance from the pupil to the retina is approximately 24 mm. 

a. Suppose you look at a 180-cm-tall friend who is standing 7.4 m in front of you. Assuming your eye functions like a pinhole camera, what will be the height, in mm, of your friend's image on your retina? 

b. Suppose your friend's image begins to get bigger. How does your brain interpret this information?