Express, correct to three significant figures, 0.003597.

Analyze the question: We need to round 0.003597 to three significant figures.

Concept: Significant figures start counting from the first non-zero digit. Leading zeros (the ones after the decimal point and before the first non-zero digit) are not significant.

Solution:

1. Write the number: 0.003597
2. Leading zeros: 0.00 are not significant.
3. The significant digits are 3, 5, 9, 7. The first three are 3, 5, 9.
4. The next digit (the 4th significant figure) is 7, which is 5 or more, so we round up the third digit.
5. Round 359 up to 360.
6. Put it back in place: 0.00360

The trailing zero is kept because it is the third significant figure. Writing 0.0036 would show only two significant figures.

Checking the options:

• A. 0.359 is wrong because the place value is wrong.
• B. 0.004 is only 1 significant figure.
• C. 0.00360 has 3 significant figures and is correctly rounded.
• D. 0.00359 is wrong because it was truncated and not rounded up.

Answer: C. 0.00360

Tip: When you round up and get a 9 that turns into 10, it carries over (359 becomes 360). Also, never drop the trailing zero when a question asks for a specific number of significant figures. It shows the precision you were asked for.