Final Answer:
The number 386.71, expressed to two significant figures, is 390.
Step-by-step explanation:
When expressing a number to a certain number of significant figures, we round the number to the desired precision. In this case, we are rounding to two significant figures. The first significant figure is the 3, and the second significant figure is the 8. The digit following the second significant figure is 6, which is equal to or greater than 5. Therefore, we round up the last significant figure (8) to 9. The final rounded number is 390.
In mathematical terms, the process involves identifying the desired number of significant figures and determining whether the digit following the last significant figure is 5 or greater. If it is, we round up the last significant figure; otherwise, we keep it unchanged. In the given number 386.71, rounding to two significant figures results in 390.
Expressing numbers to the correct number of significant figures is essential for maintaining precision and conveying the appropriate level of accuracy in scientific, mathematical, and engineering contexts. Rounding ensures that the reported value aligns with the precision of the measurement or calculation, providing clear and concise information to others who may use or interpret the data.