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2 years ago

Which figure has 90 rotational symmetry?

Mathematics

2 answers:

elena-14-01-66 [18.8K]2 years ago

7 0

The correct answer is A)

aliya0001 [1]2 years ago

6 0

It should be D) i think

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A simple random sample of size nequals81 is obtained from a population with mu equals 83 and sigma equals 27. (a) Describe the

Ivanshal [37]

Answer:

a) $\bar X \sim N (\mu, \frac{\sigma}{\sqrt{n}})$

With:

$\mu_{\bar X}= 83$

$\sigma_{\bar X}=\frac{27}{\sqrt{81}}= 3$

b) $z= \frac{89-83}{\frac{27}{\sqrt{81}}}= 2$

$P(Z>2) = 1-P(Z$

c) $z= \frac{75.65-83}{\frac{27}{\sqrt{81}}}= -2.45$

$P(Z$

d) $z= \frac{89.3-83}{\frac{27}{\sqrt{81}}}= 2.1$

$z= \frac{79.4-83}{\frac{27}{\sqrt{81}}}= -1.2$

$P(-1.2$

Step-by-step explanation:

For this case we know the following propoertis for the random variable X

$\mu = 83, \sigma = 27$

We select a sample size of n = 81

Part a

Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

$\bar X \sim N (\mu, \frac{\sigma}{\sqrt{n}})$

With:

$\mu_{\bar X}= 83$

$\sigma_{\bar X}=\frac{27}{\sqrt{81}}= 3$

Part b

We want this probability:

$P(\bar X>89)$

We can use the z score formula given by:

$z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And if we find the z score for 89 we got:

$z= \frac{89-83}{\frac{27}{\sqrt{81}}}= 2$

$P(Z>2) = 1-P(Z$

Part c

$P(\bar X$

We can use the z score formula given by:

$z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And if we find the z score for 75.65 we got:

$z= \frac{75.65-83}{\frac{27}{\sqrt{81}}}= -2.45$

$P(Z$

Part d

We want this probability:

$P(79.4 < \bar X < 89.3)$

We find the z scores:

$z= \frac{89.3-83}{\frac{27}{\sqrt{81}}}= 2.1$

$z= \frac{79.4-83}{\frac{27}{\sqrt{81}}}= -1.2$

$P(-1.2$

8 0

2 years ago

Find the slope of the line that passes through the two points (0,1) and (-8, -7)

Crazy boy [7]

Answer:

<h3>The slope of the line is 1</h3>

Step-by-step explanation:

The slope of a line is found by using the formula

$m = \frac{y2 - y1}{x2 - x1}$

where

m is the slope and

(x1 , y1) and ( x2 , y2) are the points

Substituting the above values into the above formula we have

Slope of the line that passes through

(0,1) and (-8, -7) is

$m = \frac{ - 7 - 1}{ - 8 - 0} = \frac{ - 8}{ - 8} = 1$

<h3>The slope of the line is 1</h3>

Hope this helps you

5 0

2 years ago

Find the equation of the line which has slope of -5 and y-intercept 7. Give your answer in the form y=mx+b

zhuklara [117]

Answer:

y = - 5x + 7

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + b ( m is the slope and b the y- intercept )

Here m = - 5 and b = 7, thus

y = - 5x + 7 ← equation of line

3 0

2 years ago

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Lyrx [107]

Answer:

1- 0.123

2- 0.0745

3- 0.9706

5 0

2 years ago

elve disks with the given measurements are stacked on top of each other. Which expression does NOT give the volume of the cylind

slava [35]

I don't even know for real

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2 years ago

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