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4 years ago

What is the value of a? 27.5 45 90 50

Mathematics

2 answers:

Valentin [98]4 years ago

7 0

90. The measure of an inscribed angle is half of that of the measure of its arc, and the measure of the angle corresponding with arc a is 45. 45*2 is 90, so 90 is the measure of arc a.

weeeeeb [17]4 years ago

6 0

Answer: 90

Step-by-step explanation:

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Solve this system of equations. <br> x-y=2 <br> 2.5x + y =5

aev [14]

Answer:

x=2, y=0. (2, 0).

Step-by-step explanation:

x-y=2

2.5x+y=5

---------------

x=y+2

2.5(y+2)+y=5

2.5y+5+y=5

3.5y=5-5

3.5y=0

y=0/3.5

y=0

x=0+2=2

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3 years ago

I NEED HELP ASAP BEFORE MARCH 26th <br> Find the Value of X

leva [86]

Answer:

Step-by-step explanation:

90+45=135 180-135 is 45

7 0

3 years ago

12. The Movieplex has 264 seats. Movie tickets

defon

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3 years ago

Determine the type and number of solutions of −4x2 − 3x + 7 = 0.

Kaylis [27]

Answer:

Step-by-step explanation:

You have to use the discriminant for this. If the quadratic is $-4x^2-3x+7$ , then

a = -4, b = -3, and c = 7. The formula for finding the discriminant is

$D=b^2-4ac$ which comes from the quadratic formula, but without the square root sign. Filling in:

$D=(-3)^2-4(-4)(7)$ which simplifies down to

D = 9 + 112 so

D = 121. This is a perfect square, so the solutions will be 2 real. Just so you know, you will NEVER have a solution like the one offered in the third choice down. If you have one imaginary root, you will ALWAYS have a second by the conjugate rule.

7 0

3 years ago

The cost of Internet access. How much do users pay for Internet service? Here are the monthly fees (in dollars) paid by a random

Ivanshal [37]

Answer:

$20.9-2.01\frac{7.65}{\sqrt{50}}=18.73$

$20.9+2.01\frac{7.65}{\sqrt{50}}=23.07$

The 95% confidence interval would be given by (18.73;23.07)

Step-by-step explanation:

Assuming these data

20 40 22 22 21 21 20 10 20 20

20 13 18 50 20 18 15 8 22 25

22 10 20 22 22 21 15 23 30 12

9 20 40 22 29 19 15 20 20 20

20 15 19 21 14 22 21 35 20 22

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

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

First we need to find the sample mean with the following formula:

$\bar X= \frac{\sum_{i=1}^n X_i}{50}=20.9$

And in order to find the sample standard deviation we can use the following formula:

$s= \sqrt{\frac{\sum_{i=1}^n (x_i -\bar x)^2}{n-1}}=7.65$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=50-1=49$

Since the Confidence is 0.95or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,49)".And we see that $t_{\alpha/2}=2.01$

Now we have everything in order to replace into formula (1):

$20.9-2.01\frac{7.65}{\sqrt{50}}=18.73$

$20.9+2.01\frac{7.65}{\sqrt{50}}=23.07$

So on this case the 95% confidence interval would be given by (18.73;23.07)

8 0

3 years ago