How do u get the answer for 42x3/6

A triangular pyramid has lateral faces with bases of 6 meters and heights of 9 meters. The area of the base of the pyramid is 15

charle [14.2K]

Bases+faces=surface area
15.6+81=96.6
Because 1/2*6*9=27*3=81

4 0

3 years ago

Read 2 more answers

Emma uses a 250 meters roll of crepe paper to make steamers how many dekameters of crepe paper does Emma use

Ksivusya [100]

The dekameter (or decameter) first needs to be a translated into how many the meters. deka means 10, so a dekameter it must be 10 meters. So we have to divide 250 by 10, and then we will come up with 25 dekameters.
hope that helps!!

6 0

3 years ago

A random sample of size n1= 25, taken from a normal population with a standard deviation σ1= 5, has a mean X1= 80. A second rand

sesenic [268]

Answer:

The 94% confidence interval would be given by $2.898 \leq \mu_1 -\mu_2 \leq 7.102$

Step-by-step explanation:

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".

$\bar X_1 =80$ represent the sample mean 1

$\bar X_2 =75$ represent the sample mean 2

n1=25 represent the sample 1 size

n2=36 represent the sample 2 size

$\sigma_1 =5$ sample standard deviation for sample 1

$\sigma_2 =3$ sample standard deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest.

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm z_{\alpha/2}\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =80-75=5$

Since the Confidence is 0.94 or 94%, the value of $\alpha=0.06$ and $\alpha/2 =0.03$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.03,0,1)".And we see that $z_{\alpha/2}=1.88$

The standard error is given by the following formula:

$SE=\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}}$

And replacing we have:

$SE=\sqrt{\frac{5^2}{25}+\frac{3^2}{36}}=1.118$

Confidence interval

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

$5-1.88\sqrt{\frac{5^2}{25}+\frac{3^2}{36}}=2.898$

$5+1.8\sqrt{\frac{6^2}{36}+\frac{7^}{49}}=7.102$

So on this case the 94% confidence interval would be given by $2.898 \leq \mu_1 -\mu_2 \leq 7.102$

7 0

3 years ago

The owner of an office building is expanding the length and width of a parking lot by the same amount. The lot currently measure

nasty-shy [4]

Present area = 120 * 80 = 9600 ft^2 so the new area will be 9600 + 4400 = 14000

So if increase in length = x we have

(x + 120)(x + 80) = 14,000

x^2 + 200x + 9600 - 14000 = 0

x^2 + 200x - 4400 = 0

x = 20 feet answer

4 0

3 years ago

Judith is digging for sandstone at a geological site. She has 160 meters of rope and 4 stakes to mark off a rectangular area. Wh

kondaur [170]

The 2 lengths + 2 widths of the rectangle will equal 160 meters
So, for example, length = 50 m and width = 30m would fit the bill

2*50 + 2*30 = 160 m

3 0

3 years ago