Question

Answer to this???????

Answer 1

Answer: 4.2

Step-by-step explanation: First, you'd need to re-arrange the decimals so, you can get 4.65.........

Then, you round up to get about 4.7

Another way is to round up the decimals, so your new equation:

`(21)/(5)`

Then, you'd divide to get 4.2. This way is more of an estimate than the 1st way; the 1st way is an exact answer [rounded] I hope this helped.

Answer 2

4.64

Explanation:

You want an estimate of the quotient 21.4/4.6.

Estimate

Multiplication and division by 5 are simplified by the relation ...

5 = 10/2

Here, the denominator is about 5, so the quotient is about ...

21.4 × 2/10 = 42.8/10 = 4.28 ≈ 4.3 . . . . . a first estimate; known to be low

Error correction

We notice that 4.6 is 0.4 less than 5, which is 0.8/10 = 0.08, or 8% less. That means the actual quotient will be on the order of 8% more than 4.3.

A closer estimate would be ...

4.3 + 0.08 · 4.3 = 4.3 +0.344 ≈ 4.64

An estimate of the quotient is 4.64.

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Additional comment

To compute our "error correction," we rounded 4.28 up to 4.3, about 2 parts in 400, making that number (4.3) be about 0.5% high. The estimate of 1/0.92 ≈ 1.08 turns out to be about 0.7% low. This means an even better estimate would add 0.2%, or about 0.009, to the estimate we have, making it about 4.653. These second-order corrections are also slightly off. The actual quotient rounds to 4.652.

Doubling a number is so easy that we elected to keep all of the digits of the numerator when we did the division by 5. This gave a more satisfying 4.3 instead of 4 as the first estimate.