i need help with this!

Answer:

Step-by-step explanation:

6) diameter = 2 cm

Radius is half of diameter

r = 2 /2 = 1 cm

Area of circle = πr²      {Plugin r = 1 in the formula}

                      = π*1²

                      = π cm²

7) r = 7.4 cm

Area = πr²

        = π * 7.4*7.4

        = 54.76π cm²

Answer:

-8,4

Step-by-step explanation:

Answer:

Step-by-step explanation:

Remark

Complete the square for x and for y.

complete for x

x^2 + 2x + (2/2)^2

(x + 1)^2

Complete square for y

y^2 + 10y + (10/2)^2

(y + 5)^2

Now put these two together

(x + 1)^2 + (y + 5)^2 = 15 + (10/2)^2 + (2/2)^2

(x + 1)^2 + (y + 5)^2 = 15 + 25 + 1

(x + 1)^2 + (y + 5)^2 = 41

Answer

Center: (-1,-5)

radius: (sqrt(41) = 6.403

Answer:

perimeter of a square is 3 + 3 + 3 + 3 = 12 (cm)

Step-by-step explanation:

Or use the formula P = 4a = 4(3) = 12 (cm)

Answer:

x = (9√2)/2

Step-by-step explanation:

Reference angle = 45°

Hypotenuse length = 9

Adjacent length = x

Apply the trigonometric ratio CAH:

Cos 45° = Adj/Hyp

Cos 45° = x/9

Multiply both sides by 9

9*Cos 45 = x

9*1/√2 = x (cos 45 = 1/√2)

9/√2 = x

Rationalize

(9*√2)/2 = x

x = (9√2)/2

Answer:

Step-by-step explanation:

Answer 1

Answer 2

Area = 1/2 * 6 * 11

Answej hhjb hgygvhgvhgvhgvhvhgvhvhvgh

Answer:

y=7+4 and y=7+3

Step-by-step explanation:

Answer:

B. 2(11A + 7)

Step-by-step explanation:

The common factor of 22 and 14 is 2

Answer:

Choice C

Step-by-step explanation:

You find the ratio, so every if 4 McDonalds is $28 thats 4:28

You find the unit rate 1:x

divide each side by 4 and the unit rate is 7. Graph c shows cordinate (1,7)

Answer:

it's your answer and make me barinly least

Answer: 13%

Step-by-step explanation:

To answer this question we can simply take her raised salary by her old salary...

(Put this into a calculator) 7300/56800=0.13

$7300 is 13% of her old salary

Answer:

The point estimate for the true difference between the population means is of -2.62 years.

The 95% confidence interval for the difference between the true mean ages for cars owned by students and faculty is between -3.4 years and -1.84 years.

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem, and subtraction between normal variables.

Central Limit Theorem

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

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

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction of normal variables:

When we subtract normal variables, the mean is the subtraction of the mean, while the standard deviation is the square root of the sum of variances.

A sample of 138 cars owned by students had an average age of 5.13 years. The population standard deviation for cars owned by students is 3.45 years.

This means that:

[tex]\mu_{s} = 5.13, \sigma_{s} = 3.45, n = 138, s_s = \frac{3.45}{\sqrt{138}} = 0.2937[/tex]

A sample of 111 cars owned by faculty had an average age of 7.75 years.  The population standard deviation for cars owned by faculty is 2.08 years.

This means that [tex]\mu_{f} = 7.75, \sigma_{f} = 2.08, n = 111, s_f = \frac{2.08}{\sqrt{111}} = 0.2658[/tex]

Difference between the true mean ages for cars owned by students and faculty.

s - f

Mean:

[tex]\mu = \mu_s - \mu_f = 5.13 - 7.75 = -2.62[/tex]

This is the point estimate for the true difference between the population means.

Standard deviation:

[tex]s = \sqrt{s_s^2+s_f^2} = \sqrt{0.2937^2+0.2658^2} = 0.3961[/tex]

Confidence interval:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = zs = 1.96*0.3961 = 0.78[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is -2.62 - 0.78 = -3.4

The upper end of the interval is the sample mean added to M. So it is -2.62 + 0.78 = -1.84

The 95% confidence interval for the difference between the true mean ages for cars owned by students and faculty is between -3.4 years and -1.84 years.

Answer:

8x-11

Step-by-step explanation:

3x+5x=8x

-6+-5=-11

8x-11

Answer:

8x-11 hope nthisbelps sorry if im wrong

Step-by-step explanation:

Answer:

b) 270 ≥ 40.18d + 3.75

Step-by-step explanation:

Per day is a variable, so it's 40.18d

Per mile is also a variable so 0.05m

40.18d + 0.05m ≤ 270

40.18d + 0.05(75) ≤ 270

40.18d + 3.75 ≤ 270

Answer: 270 ≥ 40.18d + 3.75

Answer:

10 10 and 20

Step-by-step explanation:

.......ur welcome........

Answer:

$125.2-discount

$500.8-sale price

Step-by-step explanation:

hope it helps

Step-by-step explanation:

Given - In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of thermal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.

Type            ni                xi                  si

Graded       42           0.486            0.187

No-fines      42           0.359           0.158

To find - a. Formulate the above in terms of a hypothesis testing problem.

b. Give the test statistic and its reference distribution (under the null hypothesis).

c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.

Proof -

a.)

Hypothesis testing problem :

H0 : There is significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

H1 : There is no significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

b)

Test statistic :

[tex]Z = \frac{x_{1} - x_{2} }{\sqrt{\frac{s_{1} ^{2} }{n_{1}} + \frac{s_{2}^{2} }{n_{2}} } }[/tex]

[tex]Z = \frac{0.486 - 0.359 }{\sqrt{\frac{0.03496 }{42} + \frac{0.02496 }{42} } }[/tex]

[tex]Z = \frac{0.127 }{\sqrt{0.001468}}[/tex]

[tex]Z = \frac{0.127 }{0.0377}[/tex]

⇒Z(cal) = 3.3687

Z(tab) = 1.96

As Z (cal) > Z(tab)

So, we reject H0 at 5% Level of significance

p-value = 0.99962

Hence

There is significant difference in mean conductivity at the two materials.

Answer:

C

Step-by-step explanation:

Answer:

The Answer is C

Step-by-step explanation:

There are three 40s and eight 50s none of the others have these

Answer:

The leghts of AB is 9 because both of the triangles are symmetrical. But also, this is a Equilateral triangle, which means that both of the sides are the same lengths (AB=AC)

Answer:

Number of whole tiles need = 120,000 tiles

Step-by-step explanation:

Given:

Area of room = 300 m²

Dimension of each tile = 5cm x 5cm

Find:

Number of whole tiles need

Computation:

Dimension of tile in meter = 5 /100 = 0.05 m

Area of each tile = 0.05 x 0.05

Area of each tile = 0.0025 m²

Number of whole tiles need = Area of room / Area of each tile

Number of whole tiles need = 300 / 0.0025

Number of whole tiles need = 120,000 tiles

Total 120,000 tiles need to cover 300 m² room.

Answer:

23

Step-by-step explanation:

Let X be a random variable denoting pulse rates of females as described, with mean µ = 74.0 bpm and standard deviation σ = 12.5 bpm. Then

P(70 < X < 78) = P((70 - µ)/σ < (X - µ)/σ < (78 - µ)/σ)

… = P(-0.32 < Z < 0.32)

… = P(Z < 0.32) - P(Z < -0.32)

… ≈ 0.6255 - 0.3745

… ≈ 0.2510

where Z is normally distributed with mean 0 and s.d. 1.

• • •

Next, you sample 25 females from the population and want to find the probability that their average falls between 70 and 78 bpm. Let [tex]X_i[/tex] denote the pulse rate of the i-th woman from the sample, and let Y be the random variable for the sample mean; that is,

[tex]Y=\displaystyle\sum_{i=1}^{25}\frac{X_i}{25}[/tex]

Recall that a sample of size n taken from a normal distribution with mean µ and s.d. σ has a mean that is also normally distributed with mean µ and s.d. σ/√n.

The mean stays the same, µ = 74.0, but now the s.d. is σ/√n = σ/5 = 2.5. So we have

P(70 < Y < 78) = P((70 - µ)/(σ/5) < (Y - µ)/(σ/5) < (78 - µ)/(σ/5))

… = P(-1.6 < Z < 1.6)

… = P(Z < 1.6) - P(Z < -1.6)

… ≈ 0.9452 - 0.0548

… ≈ 0.8904

9514 1404 393

Answer:

  (d)

Step-by-step explanation:

The purpose of the mnemonic SOH CAH TOA is to help you remember that ...

   Tan = Opposite/Adjacent

Answer:

The area of the triangle is 168 meters

Step-by-step explanation:

Formula to find the area of a triangle:

Area = 1/2 Base x Height

So, first you need to identify the base and the height. The base is 16m + 8m, and the height is 14m. All you have to do is plug in the numbers:

Area = 1/2 (16 + 8) x 14

Then, you solve:

Area = 1/2 (16 + 8) x 14

Area = 1/2 24 x 14

Area = 1/2 336

Area = 168 meters

So, the area of the triangle is 168 meters

Answer:

it is 2 1/2

Step-by-step explanation:

I hope this helps