Find the volume of this rectangle pyramid

daniel had $25to spend at tje fair. If the admission to the fair is $4 and the rides cost $1.50 each is the greatest number of r

MakcuM [25]

$25 - $4
= $21 for rides

21/1.5
= 14

He can go on 14 rides max.

5 0

3 years ago

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Circular tracts of land with diameters 900 meters, 700 meters and 600 meters are tangent to each other externally. There are hou

Rudik [331]

Answer:

$\alpha=69.28^o$

$\beta=61.26^o$

$\gamma=49.46^o$

$A=227980.26\ m^2$

Step-by-step explanation:

Triangle Solving

If we had a triangle will its three sides of known length, we can solve for the rest of the parameters of the triangle, i.e. the area, perimeter and internal angles.

The three circles have diameters 900 m, 700 m and 600 m and are tangent to each other externally. The distances from their centers (where houses are located) are the sum of each pair of the radius of the circles. Thus, the sides of the triangle are

$x=450+350=800$

$y=450+300=750$

$z=350+300=650$

The internal angles can be computed by using the cosine's law

$x^2=y^2+z^2-2yzcos\alpha$

$y^2=x^2+z^2-2xzcos\beta$

$z^2=x^2+y^2-2xycos\gamma$

Where \alpha, \beta and \gamma are the opposite angles to x, y and z respectively. Solving for each one of them:

$\displaystyle cos\alpha=\frac{y^2+z^2-x^2}{2yz}$

$\displaystyle cos\alpha=\frac{750^2+650^2-800^2}{2\cdot 750\cdot 650}$

$cos\alpha=0.3538$

$\alpha=69.28^o$

Similarly

$\displaystyle cos\beta=\frac{x^2+z^2-y^2}{2xz}$

$\displaystyle cos\beta=\frac{800^2+650^2-750^2}{2\cdot 800\cdot 650}$

$cos\beta=0.4808$

$\beta=61.26^o$

The other angle is computed now

$\displaystyle cos\gamma=\frac{x^2+y^2-z^2}{2xy}$

$\displaystyle cos\gamma=\frac{800^2+750^2-650^2}{2\cdot 800\cdot 750}$

$cos\gamma=0.65$

$\gamma=49.46^o$

The area can be found by

$\displaystyle A=\frac{1}{2}x.y.sin\gamma$

$\displaystyle A=\frac{1}{2}\cdot 800\cdot 750\cdot sin49.46^o$

$A=227980.26\ m^2$

8 0

3 years ago

National data in the 1960's showed that about 44% of the adult population had never smoked cigarettes. In 1995 a national health

Marta_Voda [28]

Answer:

a) $0.52 - 1.96\sqrt{\frac{0.52(1-0.52)}{881}}=0.487$

$0.52 + 1.96\sqrt{\frac{0.52(1-0.52)}{881}}=0.553$

The 95% confidence interval would be given by (0.487;0.553)

b) After see the confidence interval we see that the lower limits 0.487>0.44 with 0.44 or 44% the estimated proportion for 1960, we can conclude that we have a significant increase in the adult proportion had never smoked cigarettes.

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".

Solution to the problem

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

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

$\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$

If we replace the values obtained we got:

$0.52 - 1.96\sqrt{\frac{0.52(1-0.52)}{881}}=0.487$

$0.52 + 1.96\sqrt{\frac{0.52(1-0.52)}{881}}=0.553$

The 95% confidence interval would be given by (0.487;0.553)

Part b

After see the confidence interval we see that the lower limits 0.487>0.44 with 0.44 or 44% the estimated proportion for 1960, we can conclude that we have a significant increase in the adult proportion had never smoked cigarettes at 5% of significance.

4 0

3 years ago

Determine if the relation is a function and explain. a. {(-5,2), (-2,5), (0,7), (0,9)}

otez555 [7]

By definition we have to:
A mathematical function is a relationship that is established between two sets, through which each element of the first set is assigned a single element of the second set or none.
The initial set or starting set is also called the domain; the final set or set of arrival, meanwhile, can be called codomain.
We have the following information:
{(-5.2), (-2.5), (0.7), (0.9)}
The data does not represent a function because two different values of the range belong to an element of the domain:
(0.7)
(0.9)
Answer:
The relation is not a function.

4 0

3 years ago

Which is the next step in following construction of a regular hexagon

irinina [24]

Answer:

The square is the next step

Step-by-step explanation:

5 0

3 years ago

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