College

What is the product of [tex]$8.2 \times 10^9$[/tex] and [tex]$4.5 \times 10^{-5}$[/tex] in scientific notation?

A. [tex]$36.9 \times 10^{-45}$[/tex]
B. [tex]$12.7 \times 10^4$[/tex]
C. [tex]$3.69 \times 10^5$[/tex]
D. [tex]$3.69 \times 10^{14}$[/tex]

Answer :

To find the product of
[tex]$$8.2 \times 10^9 \quad \text{and} \quad 4.5 \times 10^{-5},$$[/tex]
we follow these steps:

1. Multiply the coefficients:

Multiply [tex]$8.2$[/tex] by [tex]$4.5$[/tex]:
[tex]$$
8.2 \times 4.5 = 36.9.
$$[/tex]

2. Combine the powers of 10:

Since the powers have the same base, add the exponents:
[tex]$$
10^9 \times 10^{-5} = 10^{9+(-5)} = 10^4.
$$[/tex]

At this point, the multiplication gives:
[tex]$$
36.9 \times 10^4.
$$[/tex]

3. Normalize the result:

In standard scientific notation, the coefficient must be between [tex]$1$[/tex] and [tex]$10$[/tex]. The number [tex]$36.9$[/tex] is not in this range. We can express [tex]$36.9$[/tex] as:
[tex]$$
36.9 = 3.69 \times 10^1.
$$[/tex]

Substitute this into the product:
[tex]$$
36.9 \times 10^4 = (3.69 \times 10^1) \times 10^4.
$$[/tex]

4. Combine the exponents:

Combine [tex]$10^1$[/tex] and [tex]$10^4$[/tex]:
[tex]$$
10^1 \times 10^4 = 10^{1+4} = 10^5.
$$[/tex]

Therefore, the product in standard scientific notation is:
[tex]$$
3.69 \times 10^5.
$$[/tex]

Thus, the final answer is:
[tex]$$
\boxed{3.69 \times 10^5}.
$$[/tex]

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