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2 years ago

What are the square roots of 81? I

Mathematics

2 answers:

ipn [44]2 years ago

7 0

The square root of 81 is 9

kvasek [131]2 years ago

5 0

Answer:

Step-by-step explanation:

Square root is to multiply same number to get high number.

Example: square root of 81.

9 x 9 = 81

You might be interested in

Which correlation coefficient indicated the strongest linear relationship between the variables?

Anna35 [415]

Answer:

-0.87 has the strongest linear relationship

Step-by-step explanation:

-0.87, since it is the closest value to either one or negative one,

0.8 is the second strongest

0.65 is the third strongest

-0.52 is the least strongest

7 0

3 years ago

Evaluate the expression for s = -2. -15s2 - 9-5 + s) =

Fudgin [204]

Answer:

123

Step-by-step explanation:

s=-2

-15s^2-9(-5+s)

=-15s^2+45-9s

=-15s^2-9s+45

=15(-2)^2-9×(-2)+45

=15×4+18+45

=60+18+45

=123

6 0

2 years ago

Please help me with this question.

mixas84 [53]

Answer:

Step-by-step explanation:

In a triangle, the sum of any two sides must be bigger than the third.

For the first one, 10+20=30 is not greater than 30, so this is not correct.

For B, 122+137 = 259 > 257, 257+137>122 , and 257 + 122 > 137. This works

For C, 8.6 + 2.7 = 11.3 < 12.2, so this does not work

For D, 1/6 + 1/5 = 5/(6*5) + 6/(6*5) = 5/30 + 6/30 = 11/30 < 1/2 = 15/30, so this does not work

7 0

3 years ago

A random sample of 20 students yielded a mean of ¯x = 72 and a variance of s2 = 16 for scores on a college placement test in mat

Helen [10]

Answer:

The 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =16$ represent the sample variance

s=4 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=98% or 0.98

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 mean or variance 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.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

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 the sample variance is given and for the sample deviation is just the square root of the sample variance.

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

$df=n-1=20-1=19$

Since the Confidence is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and we can use excel, a calculator or a table to find the critical values.