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3 years ago

Please help with this question PLEASE!

Mathematics

1 answer:

yuradex [85]3 years ago

6 0

Answer:

48 cm²

Step-by-step explanation:

The copper part is two equal triangles, find a triangle's area by counting squares and multiply by two.

Total copper=(Triangle area)(2)

=b(h)(½)(2)

=b(h)

=(6)(8)

=48 cm²

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Step-by-step explanation:

The area of a parallelogram is just b*h

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3 years ago

What is 96 divided by 7 please help is is due by midnight

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3 years ago

A study of peach trees found that the average number of peaches per tree was 725. The standard deviation of the population is 70

TEA [102]

Answer:

She needs to sample 189 trees.

Step-by-step explanation:

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

$\alpha = \frac{1 - 0.95}{2} = 0.025$

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

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

The standard deviation of the population is 70 peaches per tree.

This means that $\sigma = 70$

How many trees does she need to sample to obtain an average accurate to within 10 peaches per tree?

She needs to sample n trees.

n is found when M = 10. So

$M = z\frac{\sigma}{\sqrt{n}}$

$10 = 1.96\frac{70}{\sqrt{n}}$

$10\sqrt{n} = 1.96*70$

Dividing both sides by 10:

$\sqrt{n} = 1.96*7$

$(\sqrt{n})^2 = (1.96*7)^2$

$n = 188.2$

Rounding up:

She needs to sample 189 trees.

3 0

3 years ago

Please help I have spent hours trying to do...

Igoryamba

Answer:

914.4 mm
0.0479594 km

Step-by-step explanation:

For units conversion, use a conversion factor ratio with the units you do want in the numerator and the units you don't want in the denominator. The numbers in the numerator and denominator give the ratio a value of 1: the numerator is equal to the denominator--just in different units.

1. For feet to mm, you need a couple of additional conversion factors besides the ones shown:

1 foot = 12 in

1 cm = 10 mm

So, the conversion is ...

$(3\text{ ft})\times\dfrac{12\text{ in}}{1\text{ ft}}\times\dfrac{2.54\text{ cm}}{1\text{ in}}\times\dfrac{10\text{ mm}}{1\text{ cm}}=3\times12\times2.54\times10\text{ mm}\\\\=\boxed{914.4\text{ mm}}$

2. The additional factor you need for this problem is ...

1 mile = 5280 feet

So, the conversion is ...

$(157\text{ ft})\times\dfrac{1\text{ mi}}{5280\text{ ft}}\times\dfrac{1\text{ km}}{0.62\text{ mi}}=\dfrac{157}{5280\times0.62}\text{ km}\\\\\approx\boxed{0.0479594\text{ km}}$

_____

<em>Additional comment</em>

You can use Google to do units conversion by typing "3 feet to mm" or "157 feet to km". However, the conversion factor for the latter will be more exact than the one given in this problem. Hence the Google answer to the second question will not be applicable here.

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3 years ago