To round the number 27.485 to 4 significant figures, follow these steps:
1. Identify the significant figures: The significant figures are the digits that contribute to the precision of a number. For the number 27.485, the first four significant figures are:
- 2
- 7
- 4
- 8
2. Determine the rounding digit: The fourth significant figure is 8, and the next digit (the fifth digit) after the significant figures is 5.
3. Apply the rounding rule:
- If the digit following the last significant figure you want to keep is 5 or more, you round up the last significant figure.
- If the digit is less than 5, you leave the last significant figure as it is.
In this case, the next digit after 8 is 5, which means we round up.
4. Round the number: Because we need to round up the 8, we add 1 to it. Therefore:
- The initial four significant figures before rounding are 2748.
- After rounding up the 8, it becomes 27.49 when considering only four significant figures.
Therefore, the correct answer is:
D. 27.48
