Which measurement would be least likely to be written in scientific notation : the thickness of a dog hair, the radius of a period on this page ,the ounces in a cup of milk? explain

Scientific notation is either used for very large or extremely small numbers. Typically, a number such as 9000 isn't written in scientific notation, although it is possible.

First, we must assess the size of our options and pick either the largest or the smallest:
thickness of dog hair - this is be very, very small as hair is thin
radius of a period on this page  - this will also be pretty small, although most likely bigger than the dog hair
the ounces in a cup of milk - there are 8 ounces in a cup, so this is definitely not the answer

The thickness of a dog hair is the smallest out of everything, so that is the answer.

good luck