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3 years ago

The diameter of a tree trunk is 23 inches. What is the circumference?

Mathematics

2 answers:

Nadusha1986 [10]3 years ago

6 0

Answer:

72.26

Step-by-step explanation:

Circumference formula is C=2 $\pi$ r

Radius is 1/2 the diameter so, 23/2 = 11.5

11.5 will be your radius.

Now, plug your radius into your formula: 2 x $\pi$ x 11.5

and your answer will be approximately 72.26.

Vera_Pavlovna [14]3 years ago

4 0

The Image is uploaded.

You might be interested in

Use the given graph to determine the limit, if it exists.

Ahat [919]

The limit in the given graph $\lim_{x \to \ 2^{-} } f(x)$ is 3 and $\lim_{x \to \ 2^{+} } f(x)$ is -2

Given graph of a function and we have to determine the limits when x tends to 2 minus and when x tends to 2 plus.

When we see the graph we can find that the graph is not of the linear function because it is not straight line.

From x=2 and onwards it gives values values of only -2 because it is parallel to x-axis at y=-2.From x=2 and leftwards it gives values values of only 3 because it is parallel to x-axis at y=3.

Hence the limit of the function whose graph is shown is 3 and -2.

Learn more about limits at brainly.com/question/27517662

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8 0

2 years ago

Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got: