Compute all parts of given problem:
Problem: A 40 mm camera lens is used to photograph a 17 m tall tree. The lens aperture (diaphragm) opening is now set to f/8 and a 32 mm tall image of the tree is required on the camera sensor ("film").
Part I: What is the aperture diameter at this f/stop?
Part II: Derive a correct expression for diameter?
Part III: What is the distance of the tree?
Any help I can get on this problem is greatly appreciated! I'm not too familiar with this problem.