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3 years ago

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(1 pt) Which sentence best describes any trapezoid? A. It has 4 congruent sides. B. It has only 1 pair of parallel sides. C. It

has at least 2 obtuse angles. D. It has at least 2 right angles.

2 answers:

UNO [17]3 years ago

7 0

The answer is B.

Trapezoids only have 1 pair of parallel sides.<span />

wlad13 [49]3 years ago

3 0

Im not entirley sure but i do think that it is going to be A.

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What is the approximate measure of angle T in the triangle below 79° 84° 96° 101°

Anestetic [448]

The approximate measure of angle T in the given diagram is 79°. The correct option is the first option 79°

<h3>Law of Cosines</h3>

From the question, we are to determine the approximate measure of angle T

From the law of cosines, we can write that

cosT = (s² + u² - t²)/2su

From the diagram,

s = 3.9 cm

u = 2.7 cm

t = 4.3 cm

Thus,

cosT = (3.9² + 2.7² - 4.3²)/2(3.9)(2.7)

cosT = (15.21 + 7.29 - 18.49)/21.06

cosT = 4.01/21.06

cosT = 0.1904

T = cos⁻¹(0.1904)

T = 79.02°

T ≈ 79°

Hence, the approximate measure of angle T in the given diagram is 79°. The correct option is the first option 79°

Learn more on Law of Cosines here: brainly.com/question/28081595

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4 0

1 year ago

The time for a visitor to read health instructions on a Web site is approximately normally distributed with a mean of 10 minutes

klio [65]

Answer:

a) The mean is 10 and the variance is 0.0625.

b) 0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c) 10.58 minutes.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes.

This means that $\mu = 10, \sigma = 2$

Suppose 64 visitors independently view the site.

This means that $n = 64, = \frac{2}{\sqrt{64}} = 0.25$

a. The expected value and the variance of the mean time of the visitors.

Using the Central Limit Theorem, mean of 10 and variance of (0.25)^2 = 0.0625.

b. The probability that the mean time of the visitors is within 15 seconds of 10 minutes.

15 seconds = 15/60 = 0.25 minutes, so between 9.75 and 10.25 seconds, which is the p-value of Z when X = 10.25 subtracted by the p-value of Z when X = 9.75.

X = 10.25

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{10.25 - 10}{0.25}$

$Z = 1$

$Z = 1$ has a p-value of 0.8413.

X = 9.75

$Z = \frac{X - \mu}{s}$

$Z = \frac{9.75 - 10}{0.25}$

$Z = -1$

$Z = -1$ has a p-value of 0.1587.

0.8413 - 0.1587 = 0.6826.

0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c. The value exceeded by the mean time of the visitors with probability 0.01.

The 100 - 1 = 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.

$Z = \frac{X - \mu}{s}$

$2.327 = \frac{X - 10}{0.25}$

$X - 10 = 2.327*0.25$

$X = 10.58$

So 10.58 minutes.

6 0

3 years ago

Rearrange the formula to make a the subject:<br> B = 1/2h(a+b)

Mkey [24]

Answer:

Step-by-step explanation:

B=2h(a+b) #the numerator goes to the other side, the denominator then just makes it B

B/2h=a+b

2h=a+b/B

2h-a=b/B

2h-a=b(1) #factorise

6 0

3 years ago

HELP ME SO I DON’T FAIL! A regression line was calculated for three similar data sets (A, B, and C) that measure the height of a

Basile [38]

Answer:

DATA SET : A

Step-by-step explanation:

Well I answered it on Apex

6 0

3 years ago

Read 2 more answers

A Rasmussen Reports survey of 1,000 US adults found that 42% believe raising the minimum wage will help the economy. Construct a

vitfil [10]

Answer:

(0.3798, 0.4602)

Step-by-step explanation:

Let p be the true proportion of US adults who believe raising the minimum wage will help the economy. A point estimate for p is $\hat{p}=0.42$ and a good aproximation (because we have a large sample) for the standard deviation of $\hat{p}$ is $\sqrt{\hat{p}(1-\hat{p})/n}=\sqrt{0.42(0.58)/1000}=0.0156$ . Therefore, a 99% confidence interval for p is given by $\hat{p}\pm z_{\alpha/2}\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$ where $\alpha=0.01$ and $z_{\alpha/2}$ is the $\alpha/2$ th quantile of the standard normal distribution, so we have, $0.42\pm z_{0.005}0.0156$ , i.e., $0.42\pm(-2.5758)(0.0156)$ or equivalently (0.3798, 0.4602).

6 0

3 years ago