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Ghella [55]
3 years ago
8

Which is an equation of the circle with a radius of 9 units and center at (–4, 2)?

Mathematics
1 answer:
Leni [432]3 years ago
5 0
5 mabey I dontknow sorry
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4.72n - 0.1 = 8 + 0.67n
levacccp [35]
4.72n - 0.1 = 8 + 0.67n

4.72n - 0.67n = 8 + 0.1

4.05n = 8.1

4.05n/4.05 = 8.1/4.05 

n = 2
5 0
3 years ago
Each lenght is in metres Calculate DC​
Gnom [1K]

Step-by-step explanation:

ED is greater than BC

the line from B to ED ^ (which i drew ) the point it touches ED name it X. so EX will be 2 ( ED-BC)(6-4).

then u have a triangle. EX, XB and EB.

you have length of EX(2) and u have hypotenuse. so u can calculate XB using Pythagoras theorem.

15.1²=2²+XB²

15.1²-2²=XB²

224.01=XB²

XB=14.97

since XB and DC are parallel ( a rectangle is forming XBCD) so DC is also 14.97

6 0
3 years ago
A doctor wants to estimate the mean HDL cholesterol of all​ 20- to​ 29-year-old females. The number of subjects needed to estima
Ludmilka [50]

Answer:

n=(\frac{1.64(14.7)}{3})^2 =64.57 \approx 65

So the answer for this case would be n=65 rounded up to the nearest integer

And the sample size would decrease by 160-65=95 subjects

Step-by-step explanation:

1) 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".

\bar X represent the sample mean for the sample  

\mu population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size  

ME represent the margin of error

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

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

2) Solution to the problem

Since the new Confidence is 0.90 or 90%, the value of \alpha=0.1 and \alpha/2 =0.05, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that z_{\alpha/2}=1.64

Assuming that the deviation is known we can express 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 =\pm 3 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)

Replacing into formula (b) we got:

n=(\frac{1.64(14.7)}{3})^2 =64.57 \approx 65

So the answer for this case would be n=65 rounded up to the nearest integer

And the sample size would decrease by 160-65=95 subjects

8 0
3 years ago
If x = y + z and x + y =6 and x = 10, then z = _____?
7nadin3 [17]
X+y=6
x=10

10+y=6
y=-4

10=-4+z
-4+z=10
z=10+4
z=14

So the correct answer is 14
4 0
3 years ago
Read 2 more answers
- A contractor plans to build a rectangular office complex. The floor area on the first floor of the
Neko [114]

Answer:

Width = 30

Step-by-step explanation:

Area = 18x * 10y = 180xy

Length = 6xy

Width = ?

Since the shape of the office complex is a rectangle,

Area of a rectangle = length × width

180xy = 6xy × width

Width = 180xy / 6xy

Width = 30

4 0
3 years ago
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