Final answer:
The question lacks detail for finding side 'a', but the rounding methodology based on significant figures suggests that calculations must align with the least precise measurement and be rounded accordingly.
Step-by-step explanation:
The question seems to be about finding side 'a' in a mathematical context, probably related to geometry or trigonometry. However, there is insufficient information to determine what calculation is necessary to find side 'a'.
On the topic of significant figures and rounding, when working with multiple measurements like 59.35 g (to the hundredths place), 35.5 g (to the tenths place, which is the least precise), and 23.85 g, the final answer should be rounded to the least precise measurement. In this case, it is the tenths place based on 35.5 g. Additionally, the examples provided indicate the proper rounding procedures based on the digit that is dropped and whether the retained digit is even or odd.
For instance, if we add two numbers with different significant figures, say 56.0 and 3.44, our answer must be rounded to match the least number of decimal places in the least precise number. Therefore, 59.44 would be rounded to 59.4 to match the tenths place precision of 56.0.