All categories

4 years ago

a metal strip is being installed around a workbench that is 7 feet long and 3 feet wide. find how much stripping is needed

Mathematics

2 answers:

Lorico [155]4 years ago

8 0

Answer:

20 feet

Step-by-step explanation:

A metal strip is being installed around a workbench that is 7 feet long and 3 feet wide.

The shape of workbench is line a rectangle.

The length of workbench is 7 feet.

The width of workbench is 3 feet.

Perimeter of of rectangle = 2(L+W)

= 2(7+3)

= 2(10)

= 20 feet

Hence, The length of metal strip that is needed 20 feet

VikaD [51]4 years ago

5 0

Answer:

20 ft.

Step-by-step explanation:

7 ft and 3 ft.

3*2=6

7*2=14

6+14=20.

You might be interested in

I want to find the coordinates of each point of the face

Sergio039 [100]

Answer:

A) (2,5)

B) (4,4)

C) (3,2)

D) (3,-1)

E) (1,-3)

F) (-1,-3)

G) (-3,-1)

H) (-3,2)

I) (-4,4)

J) (-2,5)

K) (-1,4)

L (1,4)

7 0

3 years ago

Consider the computer output below. Fill in the missing information. Round your answers to two decimal places (e.g. 98.76). Test

slamgirl [31]

Answer:

$SE_{Mean}=\frac{s}{\sqrt{n}}=\frac{4.77}{\sqrt{19}}=1.094$

$t=\frac{98.77-100}{\frac{4.77}{\sqrt{19}}}=-1.124$

The 95% confidence interval would be given by (96.625;100.915)

a) $df=n-1= 19-1= 18$

b) $p_v =2*P(t_{18}$

If we compare the p value and a significance level for example $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis.

c) The only thing that changes is the p value and would be given by:

$p_v =P(t_{18}>-1.124)=0.862$

But again since the p value is higher than the significance level we fail to reject the null hypothesis.

Step-by-step explanation:

Previous concepts and data given

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".

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

$\bar X=98.77$ represent the sample mean

$s=4.77$ represent the sample standard deviation

n=19 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if we have significant difference on the mean of 100, the system of hypothesis would be:

Null hypothesis: $\mu = 100$

Alternative hypothesis: $\mu \neq 100$

From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

And we can calculate the Standard error for the mean like this:

$SE_{Mean}=\frac{s}{\sqrt{n}}=\frac{4.77}{\sqrt{19}}=1.094$

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

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

Since the Confidence is 0.95 or 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: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

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

$98.77-1.96\frac{4.77}{\sqrt{19}}=96.625$

$98.77+1.96\frac{4.77}{\sqrt{19}}=100.915$

So on this case the 95% confidence interval would be given by (96.625;100.915)

Part a

The degree of freedom are given by:

$df=n-1= 19-1= 18$

Part b

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

We can replace in formula (1) the info given like this:

$t=\frac{98.77-100}{\frac{4.77}{\sqrt{19}}}=-1.124$

Then since is a two sided test the p value would be:

$p_v =2*P(t_{18}$

If we compare the p value and a significance level for example $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis.

Part c

If the system of hypothesis on this case are:

Null hypothesis: $\mu = 100$

Alternative hypothesis: $\mu > 100$

The only thing that changes is the p value and would be given by:

$p_v =P(t_{18}>-1.124)=0.862$

But again since the p value is higher than the significance level we fail to reject the null hypothesis.

7 0

3 years ago

X = ????????? Geometry

bazaltina [42]

Answer:

$\boxed{x = 6}$

Step-by-step explanation:

Using Chord-Chord Power theorem:

=> (2)(x) = (4)(3)

=> 2x = 12

Dividing both sides by 2

=> x = 6

7 0

3 years ago

In May you used 900 kilowatt-hours of energy for electricity.

Sloan [31]

Answer:

a) "The total electrical energy use was 3,240,000,000 joules."

b) "The average power use is 1210 watts."

Part 1: "To generate the electricity you used, 810 L is needed."

Part 2: "To generate the electricity you used, 214.00 gal is needed."

Step-by-step explanation:

1 kilowatt-hours = $3.6x10^6$ joules

Converting 900 kilowatt-hours to joules, we have:

$900*(3.6*10^6)=3.24*10^9$ joules, or

Total Electrical Energy use = 3,240,000,000 joules

"The total electrical energy use was 3,240,000,000 joules."

The month of May has 31 days and 1 day is 24 hours. So May has:

31*24=744 hours

Now, we divide 900 kW-hr by the number of hours in the month (744 hrs) to get average power use:

$\frac{900}{744}=1.21$ kW. Since 1000 Watts = 1 kW, we multiply this by 1000 to get the answer in Watts:

1.21 * 1000 = 1210 Watts

"The average power use is 1210 watts."

Part 1:

The conversion efficiency of most generating stations is 33%. So we need to multiply the total electrical energy use (in joules) by a factor of 3 to get the amount of joules required. So:

(3.24 * 10^9)*3 = 9.72 * 10^9 joules

We divide this by 12 million joules to get the number of liters:

$\frac{9.72*10^9}{12*10^6}=810$

So, 810 liters is needed

"To generate the electricity you used, 810 L is needed."

Part 2:

We know that 0.2642 gallons is equal to 1 liters. To get the number of gallons needed, we multiply 810 by 0.2642. So:

810 * 0.2642 = 214.00 gallons

"To generate the electricity you used, 214.00 gal is needed."

7 0

3 years ago

What is the missing reason for line 5 in this proof?

Molodets [167]

Line 5 shows the division property of equality.

The division property of equality states that you can divide both sides of the equation by the same number and the equation remains the same. This equation is being divided by 4 on both sides.

5 0

3 years ago