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3 years ago

Work out the perimeter of this semicircle with radius 3cm. Give your answer in terms of π

Mathematics

1 answer:

kondaur [170]3 years ago

5 0

Step-by-step explanation:

Given :-

A semicircle is given with radius of 3cm .

And we need to find the perimeter of the semicircle . We know the perimeter as ,

$:\implies$ Perimeter = πr

$:\implies$ Perimeter = 3cm × π

$:\implies$ Perimeter = 3π cm .

Now there is the diameter of circle is 6cm . Hence totally the perimeter is ,

$:\implies$ Perimeter = 3π + 6 cm

We were supposed to give answers in terms of π .

<h3>Hence the perimeter is ( 3π + 6 ) cm</h3>

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What is -4 (-6x + 3) = 12

IgorC [24]

Answer: x = 1

Step-by-step explanation:

Simplifying

-4(-6x + 3) = 12

Reorder the terms:

-4(3 + -6x) = 12

(3 * -4 + -6x * -4) = 12

(-12 + 24x) = 12

Solving

-12 + 24x = 12

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '12' to each side of the equation.

-12 + 12 + 24x = 12 + 12

Combine like terms: -12 + 12 = 0

0 + 24x = 12 + 12

24x = 12 + 12

Combine like terms: 12 + 12 = 24

24x = 24

Divide each side by '24'.

x = 1

Simplifying

x = 1

6 0

3 years ago

Read 2 more answers

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marshall27 [118]

Sure, I have this strategy to make a sheet with questions of that chapter and do that before I study the chapter so I can see if I know a little or a lot of that chapter

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2 years ago

A confidence interval was used to estimate the proportion of statistics students that are female. A random sample of 72 statisti

jeyben [28]

Answer:

We need a sample of size at least 13.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

90% confidence interval: (0.438, 0.642).

The proportion estimate is the halfway point of these two bounds. So

$\pi = \frac{0.438 + 0.642}{2} = 0.54$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

Using the information above, what size sample would be necessary if we wanted to estimate the true proportion to within ±0.08 using 95% confidence?

We need a sample of size at least n.

n is found when M = 0.08. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.08 = 1.96\sqrt{\frac{0.54*0.46}{n}}$