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1 year ago

Find the area of the trapezoid 3cm 3cm 4cm 1cm

Mathematics

1 answer:

Snowcat [4.5K]1 year ago

6 0

Answer:

8√2 cm²

Refer to the attached page,I've shown the complete calculation over there

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Estimate the measure of the clockwise angle formed by the minute hand and the second hand, then classify the angle. A. 54°; acut

Harlamova29_29 [7]

I would go with b or a or d but not c

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3 years ago

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What is x? 6x-18+14x+38

evablogger [386]

Answer:

x= -1

Step-by-step explanation:

6x-18+14x+38

group= 20x+20

set equal to 0

20x+20=0

-20 -20

20x/20= -20/20

x= -1

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3 years ago

What is the square of 7

kkurt [141]

2.64575131106 I don’t know if you need to round the answer or not

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2 years ago

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Flow meters are installed in urban sewer systems to measure the flows through the pipes. In dry weatherconditions (no rain) the

ziro4ka [17]

Answer:

a) $\frac{(8)(30.23)^2}{20.09} \leq \sigma^2 \leq \frac{(8)(30.23)^2}{1.65}$

$363.90 \leq \sigma^2 \leq 4430.80$

Now we just take square root on both sides of the interval and we got:

$19.08 \leq \sigma \leq 66.56$

b) For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56

Step-by-step explanation:

423.6, 487.3, 453.2, 402.9, 483.0, 477.7, 442.3, 418.4, 459.0

Part a

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^8 (x_i -\bar x)^2}{n-1}}
And in order to find the sample mean we just need to use this formula:
[tex]\bar x =\frac{\sum_{i=1}^n x_i}{n}$

The sample deviation for this case is s=30.23

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

The Confidence interval is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and the critical values are:

$\chi^2_{\alpha/2}=20.09$

$\chi^2_{1- \alpha/2}=1.65$

And replacing into the formula for the interval we got:

$\frac{(8)(30.23)^2}{20.09} \leq \sigma^2 \leq \frac{(8)(30.23)^2}{1.65}$

$363.90 \leq \sigma^2 \leq 4430.80$

Now we just take square root on both sides of the interval and we got:

$19.08 \leq \sigma \leq 66.56$

Part b

For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56

4 0

3 years ago

Triangle DEF is a right triangle. What is the measure of ZEFD?<br> D<br> 57°<br> F<br> E

creativ13 [48]

Answer:

Step-by-step explanation:

Sum of measures of angles in any triangle is 180°

The maesure of right angle is 90°

So: m∠EFD = 180° - 90° - 57° = 33°

6 0

2 years ago