A person on a safari wants to take a photograph of a hippopotamus from a distance of 75.0 m. The animal is 4.00 m long and its image is to be 1.20 cm long on the film.
(a) What focal length lens should be used?
(b) What would be the size of the image if a lens of 50.0-mm focal length were used?
(c) How close to the hippo would the person have to be to capture a 1.20-cmlong image using a 50.0-mm lens?