The moon's diameter is 3.48 × 106 m, and its mean distance from the earth is 3.85 × 108 m. The moon is being photographed by a camera whose lens has a focal length of 40.0 mm.
(a) Find the diameter of the moon's image on the slide film.
(b) When the slide is projected onto a screen that is 12.4 m from the lens of the projector (f = 120.0 mm), what is the diameter of the moon's image on the screen?