Which of the following numbers contains five significant figures?

• A. 100.0
• B. 12.345
• C. 0.07080
• D. 0.004560

Answer: (B)

Verified step by step guidance

1. Understand that significant figures (sig figs) are the digits in a number that carry meaningful information about its precision, including all nonzero digits, any zeros between them, and trailing zeros in the decimal part.
2. Analyze each number to count its significant figures:
3. For 100.0, the digits are '1', '0', '0', and the trailing zero after the decimal point counts, so it has 4 significant figures.
4. For 12.345, all digits are nonzero, so each digit counts, giving 5 significant figures.
5. For 0.07080, ignore leading zeros (which are not significant), then count '7', '0', '8', and the trailing zero after the decimal point, totaling 4 significant figures; similarly, 0.004560 has 4 significant figures.