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3 votes
3 votes
PLEASE HELP!!!

Using the rules that you learned during the session, what is the answer to the following question?

55.78 * 23.7

Answers
1,321.986
1,321.99
1,322
1,320

User Andrew Kalashnikov
by
2.2k points

1 Answer

16 votes
16 votes

Answer:

(d) 1,320

Step-by-step explanation:

You want the product 55.78 × 23.7 rounded appropriately.

Significant figures

When a number has both an integer part and a decimal fraction, all of the digits are significant. Here, that means the first number has 4 significant figures, and the second number has 3 significant figures.

The number of significant figures in a product or quotient will be the least of the numbers of significant figures of the contributors. Here, the product can only have 3 significant figures.

55.78 × 23.7 = 1321.986 ≈ 1320 . . . . rounded to 3 sf

Using the rules for significant figures, the answer is 1320.

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Additional comment

Generally, the rules for significant figures apply to quantities derived from measurements. They can also be applied to estimates, where the result of computation using numbers of different precision cannot have any more accuracy than the least precise contributor.

The other useful rule in this process is that the rounding is saved for the final answer. Intermediate results should be carried to the full precision available.

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User John Babb
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2.9k points