Hello, first time poster. I'm in an optics class because I thought it would be fun, but I'm having a terrible time. And I didn't do so well on the first test. The second test is tomorrow and I want to do well on it. We were given a practice exam with 3 questions. I got two of them, but the third is still eluding me. Thank you for any guidance. 1. The problem statement, all variables and given/known data A small fish, 40cm below the surface of a lake, is viewed through a thin converging lens with focal length 20cm. the lens is located 30cm above the water. The refractive index of water is 1.33 and air is 1. Assume that the fish lies on the optical axis of the lens. 2. Relevant equations The only equation that I know of is the various forms of (1/so)+(1/si)=(1/f) 3. The attempt at a solution I followed the advice of someone else to draw a ray diagram and use Snell's law at the interface of air/water, but that got me no where. I don't know what the angles of the rays are to use Snell's law and even if I did, I'm not sure how that would help me.