A canvas tent has a single, tiny hole in its side. On the opposite wall of the

Question:

A canvas tent has a single, tiny hole in its side. On the opposite wall of the tent, 2.0 m away, you observe a dot (due to sunlight incident upon the hole) of width 2.0 mm, with a faint ring around it. What is the size of the hole in the tent? (Assume a wave length of 570 nm for the sunlight.)