Your friend is 1.8m tall.
a)When she stands 3.1m from you, what is the height of her image formed on the retina of your eye? (Consider the eye to consist of a thin lens 2.5 cm from the retina.)
b)What is the height of her image when she is 4.5m from you?
Read more:
What is the height of the image formed? - 1