7. The diameter of a water molecule is 0.000 000 000 28 meters.

a. Approximate the diameter of a water molecule by rounding to the nearest ten billionth of a meter.

b. Write your answer from part (a) as a single digit times a unit fraction with a denominator written as a power of 10 in exponential form.



Answer :

Certainly! Let's break this down step by step.

### Part (a): Rounding to the nearest ten billionth of a meter

Firstly, the given diameter of a water molecule is [tex]\(0.00000000028\)[/tex] meters, which can be written as [tex]\(2.8 \times 10^{-10}\)[/tex] meters.

To round this number to the nearest ten billionth of a meter ([tex]\(10^{-10}\)[/tex] meters):

- Observe that the diameter is already very close to [tex]\(0.0000000003\)[/tex] meters (which equals [tex]\(3 \times 10^{-10}\)[/tex]).
- Therefore, when rounding [tex]\(0.00000000028\)[/tex] meters to the nearest ten billionth, we get [tex]\(0.0000000003\)[/tex] meters.

So, the rounded diameter is:
[tex]\[ 3 \times 10^{-10} \text{ meters} \][/tex]

### Part (b): Express the rounded diameter as a single digit times a unit fraction with a denominator written as a power of 10 in exponential form

The rounded diameter is [tex]\(0.0000000003\)[/tex] meters, which equals [tex]\(3 \times 10^{-10}\)[/tex] meters.

Now, let's express [tex]\(3 \times 10^{-10}\)[/tex] meters in the form of a single digit times a unit fraction:

- The number [tex]\(3 \times 10^{-10}\)[/tex] can be considered as a single digit (3) multiplied by the power of 10.
- In scientific notation, this is already in the desired form.

The exponential form is:
[tex]\[ 3 \times 10^{-10} \][/tex]

Thus:
1. Rounded to the nearest ten billionth of a meter: [tex]\(3 \times 10^{-10}\)[/tex] meters.
2. Expressed as a single digit times a unit fraction: [tex]\(3 \times 10^{-10}\)[/tex].