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3 years ago

Help!!! please show some work so i know its right! THANKS!!!!

Mathematics

1 answer:

zhenek [66]3 years ago

7 0

Answer:

Step-by-step explanation:

90 degree angle = right angle, that's what it is. you know there's 60 degree, so the other one is 90 - 60 = 30. since it's 3 times x, it's 10.

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Two electricians are assigned to work on a remote control wiring job. One electrician works 8 1/2 hours each day, and the other

klasskru [66]

8.5 • 5 = 42.5
2.5 • 5 = 12.5
42.5 - 12.5 = 30
The first electrician worked 30 hours longer than the second electrician.

6 0

3 years ago

Which dimensions can create more than one triangle?

garri49 [273]

Answer:

three sides measuring 4 ft, 8 ft, and 10 ft

Step-by-step explanation:

To choose which dimensions that can create more than one triangle, we consider the given values carefully and how possible it will be to construct.

The only dimensions given in the option that will be possible to create more than one triangle from it, is three sides measuring 4 ft, 8 ft, and 10 ft.

4 ft, 8 ft, and 10 ft are in simple multiple of 2

4 ft, 8 ft, and 10 ft = 2 (2 ft, 4 ft, and 5 ft ), with this we can construct two triangles with three sides measuring 2 ft, 4 ft, and 5 ft.

3 0

3 years ago

The dwarves of the Grey Mountains wish to conduct a survey of their pick-axes in order to construct a 99% confidence interval ab

Dmitry_Shevchenko [17]

Answer:

The minimum sample size needed is 125.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

For this problem, we have that:

$\pi = 0.25$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

What minimum sample size would be necessary in order ensure a margin of error of 10 percentage points (or less) if they use the prior estimate that 25 percent of the pick-axes are in need of repair?

This minimum sample size is n.

n is found when $M = 0.1$

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.1 = 2.575\sqrt{\frac{0.25*0.75}{n}}$

$0.1\sqrt{n} = 2.575{0.25*0.75}$

$\sqrt{n} = \frac{2.575{0.25*0.75}}{0.1}$

$(\sqrt{n})^{2} = (\frac{2.575{0.25*0.75}}{0.1})^{2}$

$n = 124.32$

Rounding up

The minimum sample size needed is 125.

5 0

4 years ago

Find the volume of the pyramid below. 7.2 in 9.7 in

kumpel [21]

Answer:

23.28 inches (im not sure if this is correct because you need length, height, and width.)

Step-by-step explanation:

lwh

4 0

3 years ago

In the 2014 - 2015 school year, the mean score on the critical reading of the SAT was 490 with a standard deviation of 102 for j

bonufazy [111]

Answer:

The Ranking Percentile is (B) 97.5%

Explanation :

To find the percentile rank we need to find the z- score. After finding the z-score match this value with the corresponding value in z-score table.

Formula to find the z-score

Z-score= $\frac{\text { scored obtained - mean }(\mu)}{\text { standard deviation }(\sigma)}$

Substituting the values in the above equation, we find

Z-score= $\frac{(694-490)}{102}$ =2

So, the Z-score is +2

Now, the corresponding value of Z-score 2 in the table is 0.9772

or the percentile score is 97.72 ~ 97.5 .

3 0

3 years ago