To arrange the numbers in descending order, we first need to convert them to a common notation or understand their values, especially with their powers of ten. Let's analyze each option:
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A.
- \(7 \times 10^{-30}\)
- \(7.2 \times 10^{-25}\)
- \(7.2 \times 10^{-30}\)
- \(7.6 \times 10^{-25}\)
Comparing powers of ten:
- \(7.2 \times 10^{-25} > 7.6 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30}\) This is not in descending order.
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B.
- \(7.6 \times 10^{-25}\)
- \(7.2 \times 10^{-30}\)
- \(7.2 \times 10^{-25}\)
- \(7 \times 10^{-30}\)
This option places \(7.2 \times 10^{-30}\) incorrectly in sequence, as it is less than \(7.2 \times 10^{-25}\). This is not in order.
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C.
- \(7.2 \times 10^{-30}\)
- \(7 \times 10^{-30}\)
- \(7.6 \times 10^{-25}\)
- \(7.2 \times 10^{-25} \)
This option has the first two terms in the incorrect order (they should be at the end), so it is not in descending order.
-
D.
- \(7.6 \times 10^{-25}\)
- \(7.2 \times 10^{-25}\)
- \(7.2 \times 10^{-30}\)
- \(7 \times 10^{-30}\)
This option correctly places \(7.6 \times 10^{-25} > 7.2 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30}\).
Thus, option D is arranged in descending order.