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3 years ago

The area of circle Z is 64 it? What is the value of r ?

Mathematics

2 answers:

Art [367]3 years ago

4 0

Answer:

The answer is 8 guys not 4 or 4.5. It literally says on the question that its 64Pi not just 64

Step-by-step explanation:

Dennis_Churaev [7]3 years ago

3 0

Answer:

Area of a circle = π·r²

64 = π·r²

r²= 64/ π

r²= 20.37

r= 4.51 ft

OPTION A

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If r = 3.2, what is the area of the shaded region? Round your answer to the nearest hundredth. Use your calculator's value of π.

MrRa [10]

Answer: The shaded area is 99.55 units squared.

Step-by-step explanation:

r = 3.2

Now, we can see that the sides of the square are equal to two times the diameter of the circles (or four times the radius of the circles), so the length of the sides of the square is:

L = 2*(2*3.2) = 12.8

The area of the square is A1 = L^2 = 12.8*12.8 = 163.84 units squared.

the shaded semicircle has a diameter of 4 times r (so the radius is 2 times r), and the area is equal to half the area of a circle:

A2 = (1/2)*pi*(2r)^2 = (1/2)*3.14*(6.4)^2 = 64.31 units squared.

And now we must subtract the area of the four smaller circles inside the square, the area of each one is:

A3 = pi*r^2 = 3.14*(3.2)^2 = 32.15 units squared.

Then the shaded area is:

A = A1 + A2 - 4*A3 = 163.84 + 64.31 - 4* 32.15 = 99.55 units squared.

8 0

3 years ago

You are trying to estimate the average amount a family spends on food during a year. In the past the standard deviation of the a

svetoff [14.1K]

Answer:

$n=(\frac{2.58(1000)}{50})^2 =2662.56 \approx 2663$

So the answer for this case would be n=2663 rounded up to the nearest integer

Step-by-step explanation:

We have the following info:

$ME = 50$ margin of error desired

$\sigma = 1000$ the standard deviation for this case

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =50 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 99% of confidence interval now can be founded using the normal distribution. The significance is $\alpha=0.01$ . And for this case would be $z_{\alpha/2}=2.58$ , replacing into formula (b) we got:

$n=(\frac{2.58(1000)}{50})^2 =2662.56 \approx 2663$

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2 years ago

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3241004551 [841]

Answer:

x= $- \frac{18}{23}$

Step-by-step explanation:

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3 years ago

Solving square root equations<br> 8 = square root of 15x + 4

makkiz [27]

Answer:

x is 4.

Step-by-step explanation:

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Answer:

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3 years ago