Significant figures, or sig figs, play a crucial role in scientific measurements and calculations. They convey the precision of a measurement and determine how results should be reported. In this article, we will explore the significance of the number 109.0 specifically, as well as provide practical examples and a deeper understanding of how significant figures work.
What Are Significant Figures?
Significant figures are the digits in a number that contribute to its accuracy. This includes all nonzero digits, any zeros between significant digits, and any trailing zeros that are to the right of a decimal point.
Example Breakdown
For the number 109.0:
 The digits 1 and 9 are significant.
 The 0 between 1 and 9 is significant (it indicates a measured value).
 The trailing 0 after the decimal point is also significant because it indicates precision in the measurement.
Thus, 109.0 has four significant figures.
Common Questions About Significant Figures
To enhance our understanding, let's answer some common questions related to significant figures, drawing from discussions on Stack Overflow and other educational resources.
1. Why Are Significant Figures Important?
Answer: Significant figures are essential because they provide a way to express the precision of a measurement. For example, if one scientist measures a length as 109.0 cm and another measures it as 109 cm, it indicates different levels of precision. The first measurement suggests that the measurement is precise to the nearest tenth of a centimeter, while the latter does not convey this level of detail.
2. How Do You Determine Significant Figures in Calculations?
Answer: When performing calculations, the rules for significant figures must be followed:
 Addition and Subtraction: The result should be reported with the same number of decimal places as the term with the fewest decimal places.
 Multiplication and Division: The result should be reported with the same number of significant figures as the term with the fewest significant figures.
Practical Example
Let's say you have two measurements:
 Measurement A: 109.0 m (4 sig figs)
 Measurement B: 5.00 m (3 sig figs)
If you were to add these two measurements:
[ 109.0 , m + 5.00 , m = 114.0 , m ]
In this case, the result 114.0 m is correctly reported with one decimal place since 5.00 m has the fewest decimal places (two). Thus, the final result remains 114.0 m (also with 4 significant figures).
Additional Considerations

Rounding Rules: When rounding numbers to match significant figures, always look at the digit following the last significant figure to determine whether to round up or stay the same.

Leading Zeros: Any leading zeros in a number (e.g., 0.0056) are not significant. This number has two significant figures.

Exact Numbers: Numbers that are counted or defined (like 100 students or 1 meter = 100 centimeters) have an infinite number of significant figures.
Conclusion
Understanding significant figures, such as in the case of 109.0, is essential for conveying the precision of measurements in scientific and technical fields. Whether you're reporting results from an experiment or conducting calculations, paying attention to significant figures ensures accuracy and clarity in communication.
Additional Resources
For further reading and practical exercises, consider the following resources:
By mastering significant figures, you can improve the quality of your scientific reporting and enhance your precision in measurements!
Attribution: This article incorporates insights and answers inspired by discussions on Stack Overflow and other educational resources.