Round the decimal number 0.0078496 to 3 significant figures.
Answer and explanation
Correct answer: B. 0.00785
- Step 1: Significant figures begin at the first non-zero digit, which is 7. Step 2. The first three significant figures are 7, 8, 4. Step 3. The next digit is 9 (≥ 5), so round up the 4 to 5. Step 4. Result: 0.00785. Answer: 0.00785. Why not the others: 0.00784 rounds down incorrectly; 0.008 is to 1 significant figure; 0.007850 has 4 significant figures.
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