Jamie used a microscope to measure the diameter of a hair. She

Question

found that the diameter of the hair was 0.000072 meter. How is
this number written in scientific notation?
Circle the correct answer.
7.2 X 10-5
7.2 × 10-6
7.2 X 105
7.2 X 106

Answer 1

To write the number 0.000072 in scientific notation, we need to express it as a product of a number between 1 and 10 and a power of 10.

First, we move the decimal point in 0.000072 to the right until we have a number between 1 and 10. This gives us 7.2.

Next, we count how many places we moved the decimal point to the right, which is 5 places. Because we moved the decimal to the right, we represent this as a negative exponent of 10.

Thus, the scientific notation for 0.000072 is: \[ 7.2 \times 10^{-5} \]

So the correct answer is: 7.2 X 10-5