Final answer:
The exact sum of 8.176, 5.802, and 41.921 is 55.899. The estimated sum is 56, found by rounding each number to the nearest whole number before adding.
Step-by-step explanation:
The exact sum of the numbers 8.176, 5.802, and 41.921 is obtained by aligning the decimal points and adding the numbers column by column from right to left. The estimated sum can be found by rounding each number to the nearest whole number before adding.
Exact sum: 8.176 + 5.802 + 41.921 = 55.899
For the estimated sum, we round the numbers as follows: 8.176 ≈ 8, 5.802 ≈ 6, 41.921 ≈ 42. Adding these we get Estimated sum: 8 + 6 + 42 = 56.
The exact sum must be expressed with the proper number of significant figures, which in this case corresponds to the least precise measurement in the series, maintaining all decimal places as given.