Final answer:
To estimate the value of 243 divided by 18.2 by rounding each number to the nearest 10, we round 243 to 240 and 18.2 to 20, then divide to get the approximated value of 12. Significant figures should be considered to ensure the precision of the estimation matches the original numbers.
Step-by-step explanation:
The student's question asks for an estimate of the value of 243 divided by 18.2 (written as 243 : 18.2) by rounding each number to the nearest 10. To approximate this value, we first round 243 to the nearest 10, which gives us 240. Next, we round 18.2 to the nearest 10, giving us 20. Now we can perform the division with the rounded numbers: 240 ÷ 20 equals 12.
Significant figures are important in calculations, especially in scientific contexts. As per the given information about significant figures, when calculating with inexact numbers like 180, 16, and 2.20, the answer should have the same number of significant figures as the starting number with the fewest significant figures. For example, if we had a calculation with a result of 119.902, since we are only concerned with significant figures to the tenths place, the answer would be rounded to 119.9.
Similarly, when multiplying numbers such as 18,900 and 76.33 and then dividing by 0.00336, the answer should be limited to four significant figures. This concept also applies to other calculations, and when multiplying and dividing, the same rounding rules are used as in addition and subtraction.