Question

round off 5.3778 × 10³ mg to three significant figures.

Explanation:

Step1: Identify significant figures

The number is $5.3778\times 10^{1}$ mg. We want three significant - figures. The first three digits are 5, 3, and 7.

Step2: Look at the fourth digit

The fourth digit is 7. Since 7 is greater than 5, we round up the third digit.

Step3: Round the number

When we round 5.3778 to three significant figures, we get 5.38. So the number rounded to three significant figures is $5.38\times 10^{1}$ mg.

Answer:

C. $5.38\times 10^{1}$ mg