Final answer:
Proxima Centauri is approximately 2.48 × 10¹³ miles from the Sun, expressed in scientific notation.
Step-by-step explanation:
The distance from the Sun to Proxima Centauri is approximately 39,900,000,000,000 kilometers. To express this number in scientific notation, we start by placing the decimal after the first nonzero digit, making the figure 3.99. We then count how many places the decimal moved, which is 13. Therefore, the distance in scientific notation is 3.99 × 10¹³ kilometers. To convert this to miles, we use the conversion factor that 1 kilometer is approximately 0.621371 miles. Multiplying, the distance in miles is 3.99 × 10¹³ × 0.621371, which gives us roughly 2.48 × 10¹³ miles from the Sun to Proxima Centauri.