Final answer:
Significant figures are all non-zero digits, zeros between non-zero digits, and zeros at the end of a number with a decimal point. Leading zeros are not significant. The measurements given have 2, 4, 5, 3, and 5 significant figures respectively.
Step-by-step explanation:
Determining the number of significant figures in measurements is crucial for understanding precision in scientific calculations. The rules for identifying significant figures include noting all non-zero digits as significant, and for numbers with decimals, zeros within or at the end of the number (after a non-zero digit) are significant.
- 0.017 m: In this case, the two leading zeros are not significant. Only the '1' and '7' are significant, yielding 2 significant figures.
- 808.9 kg: All these digits are significant, since they're either non-zero digits or a final digit after the decimal again indicating precision. This gives us 4 significant figures.
- 1264.2 L: Here, all digits are significant because there are no leading or trailing zeros just to indicate position. We have 5 significant figures.
- 280 cg: This is slightly trickier since it might look like the zero is just a placeholder, but it actually denotes precision in the hundred's place. It counts as significant, so we have 3 significant figures.
- 3240.0 mm: The zeros are after a decimal and are therefore significant. This measurement has 5 significant figures.