Open Question: Visual angle and image size on the retina?

Please tell me the formulas to figure out the answers for each of the problems so that I know how to do them:

Suppose that the focal length of the eye (the distance from the lens to the retina) is 2 cm. Your blind spot subtends an angle of roughly 5 deg. How big is the blind spot (in cm) on your retina? (Use the focal length as the distance in the visual angle equation).

The fovea is roughly 2 deg of visual angle. What is the diameter of the fovea in cm? (Use 2 cm again as the focal length).

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