People who do very detailed work close up, such as jewellers, often can see objects clearly at much closer distance than the normal 25 cm. What is the size in mm of an image of a 0.75 mm object, such as lettering inside a ring, held at this distance? What would the size in mm of the image be if the object were held at the normal 25 cm distance?

People who do very detailed work close up, such as jewellers, often can see objects clearly at much closer distance than the normal 25 cm. What is the size in mm of an image of a 0.75 mm object, such as lettering inside a ring, held at this distance? What would the size in mm of the image be if the object were held at the normal 25 cm distance?