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3 years ago

Explain how an estimate helps you to place the decimal point when mutiplyning 3.9 times 5.3

2 answers:

7 0

It'll make it easier to multiply. If you round 3.9 to four, and 5.3 to five, it's quite easy to figure out the answer is about 20. I hope this helps! :)

Juli2301 [7.4K]3 years ago

6 0

You can round these numbers to the closes whole number; 3.9-->4 and 5.3-->5, and then you can do 5x4 to get 20; and if you multiply regularly without estimating, your answer will be around 20.

You might be interested in

What is the number that is 25 units away from -12?

Crazy boy [7]

Answer:

Step-by-step explanation:

25 - 12 = 13

6 0

3 years ago

The radius of a circle is 56 cm. Find the circumference of the circle to the nearest tenth. 351.9 cm 9,852.0 cm 112.0 cm 88.0 cm

borishaifa [10]

Alright, lets get started.

We have given a circle which has 56 cm radius.

We are asked to find its circumference.

The formula for circumference of circle = 2 pi r

Putting the value of pi and r

So the circumference = 2 * 2.142 * 56

Simplifing

Hence the circumference of circle = 351.9 cms

Answer is 351.9 cm

Hope it will help :)

7 0

3 years ago

At a family reunion, a family friend brings 20 pounds of ice and 30 cups. Which expression shows the greatest common factor, usi

Eddi Din [679]

The expression for the greatest common factor of 20 and 30 using the distributive property is 10(2 + 3)

Pounds of ice = 20

Number of cups = 30

The relation for the distributive property :

a × (b + c)

Expand ;

a × (b + c) = (a × b) + (a × c) = ab + ac

Finding the greatest common factor of 20 and 30 ;

20 = 2 × 10

30 = 3 × 10

(2 × 10) + (3 × 10)

According to the distributive property

(2 × 10) + (3 × 10) = 10(2 + 3)

Therefore, the expression for the greatest common factor is 10(2 + 3)

Learn more :brainly.com/question/15263211

6 0

3 years ago

6x – 7y = 25<br> 15x+3y = 42

Dmitrij [34]

The answer would =-1

8 0

3 years ago

The weight of an adult swan is normally distributed with a mean of 26 pounds and a standard deviation of 7.2 pounds. A farmer ra

Snezhnost [94]

Let $X$ denote the random variable for the weight of a swan. Then each swan in the sample of 36 selected by the farmer can be assigned a weight denoted by $X_1,\ldots,X_{36}$ , each independently and identically distributed with distribution $X_i\sim\mathcal N(26,7.2)$ .

You want to find

$\mathbb P(X_1+\cdots+X_{36}>1000)=\mathbb P\left(\displaystyle\sum_{i=1}^{36}X_i>1000\right)$

Note that the left side is 36 times the average of the weights of the swans in the sample, i.e. the probability above is equivalent to

$\mathbb P\left(36\displaystyle\sum_{i=1}^{36}\frac{X_i}{36}>1000\right)=\mathbb P\left(\overline X>\dfrac{1000}{36}\right)$

Recall that if $X\sim\mathcal N(\mu,\sigma)$ , then the sampling distribution $\overline X=\displaystyle\sum_{i=1}^n\frac{X_i}n\sim\mathcal N\left(\mu,\dfrac\sigma{\sqrt n}\right)$ with $n$ being the size of the sample.

Transforming to the standard normal distribution, you have

$Z=\dfrac{\overline X-\mu_{\overline X}}{\sigma_{\overline X}}=\sqrt n\dfrac{\overline X-\mu}{\sigma}$

so that in this case,

$Z=6\dfrac{\overline X-26}{7.2}$

and the probability is equivalent to

$\mathbb P\left(\overline X>\dfrac{1000}{36}\right)=\mathbb P\left(6\dfrac{\overline X-26}{7.2}>6\dfrac{\frac{1000}{36}-26}{7.2}\right)$
$=\mathbb P(Z>1.481)\approx0.0693$

5 0

3 years ago