Here is the problem which I am struggling on, please help me!
Problem: During a lunar eclipse, a picture of the moon (which has a diameter of 3.48 × 106 m and is 3.86 × 108 m from the earth) is taken with a camera whose lens has a focal length of 320 mm.
Part A. What is the diameter of the image on the film?
Part B. What percent is this of the width of a 24mm × 36mm color slide?
I need help for above question.