person is 1.9 m tall. Where should he place the top of a mirror on the wall so he can see the top of his head? Assume his eyes are 5.1 cm below the top of his head. Find a minimal vertical distance from the level of the person's eye

The minimal vertical distance from the level of the person's eye is 2.55 cm.

Explanation:

Given;

height of the person = 1.9 m

his eyes are 5.1 cm below the top of his head

If top of his head is the same distance from the mirror as his eyes is from the mirror, then the top of the mirror must be half of his eyes level.

Therefore, the minimal vertical distance from the level of the person's eye is ¹/₂ x 5.1 cm = 2.55 cm

The minimal vertical distance of the mirror from the level of the person's eye is 2.55 cm.