V=n/t+10 solve for n

A chord is 15 cm long. It is 9 cm from the center of the circle. What is the radius of the circle?

irakobra [83]

Answer:

Step-by-step explanation:

Given a chord of distance of 15cm, if it is 9cm from the center of a circle, this means that the 9cm length will be projecting from the centre of the circle perpendicular to the chord and passing through its centre.

Since the radius of a circle is a line that is drawn from the centre of a circle to ts circumference, the set up will form a right angles triangle within the circle with the hypotenuse as the radius and the other two sides as the opposite and adjacent respectively. Using the Pythagoras theorem to get the length of the radius (hypotenuse);

hyp² = opp² + adj²

Let the opposite be the 9cm length

Adjacent will be half of the chord length = 15/2 = 7.5cm

Substituting this values into the formula we will have;

hyp² = 9² + 7.5²

hyp² = 81+56.25

hyp² = 137.25

hyp² = √137.25

hyp = 11.72

Hence the radius of the circle is approximately 11.72 cm long

5 0

2 years ago

When the sample size and the sample proportion remain the same, a 90 percent confidence interval for a population proportion p w

deff fn [24]

Answer:

A 90% confidence interval for p will be narrower than the 99% confidence interval.

Step-by-step explanation:

The formula to compute the (1 - α) % confidence interval for a population proportion is:

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

Here $\hat p$ is the sample proportion.

The margin of error of the confidence interval is:

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

The MOE is dependent on:

Confidence level
Standard deviation
Sample size

The MOE is directly related to the confidence level and standard deviation.

So if any of the two increases then the MOE also increases, thus widening the confidence interval.

And the MOE is inversely related to the sample size.

So if the sample increases the MOE decreases and vice versa.

It is provided that the sample size and the sample proportion are not altered.

The critical value of z for 90% confidence level is:

$z_{\alpha/2}= z_{0.10/2}=z_{0.05}=1.645$

And the critical value of z for 99% confidence level is:

$z_{\alpha/2}= z_{0.05/2}=z_{0.05}=1.96$

So as the confidence level increases the critical value increases.

Thus, a 90% confidence interval for p will be narrower than the 99% confidence interval.

6 0

2 years ago

Five times a number divided by 3 equals 35. WHats the solution

iren [92.7K]

5x/3=35

5x = 35*3=105

x= 105/5 = 21

double check 5 x 21 = 105

105/3 = 35

3 0

3 years ago

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Y=4x+1, 2x+y=37 substitution

VLD [36.1K]

Answer:

x = 6 and y = 25 → (6, 25)

Step-by-step explanation:

Substitute y = 4x + 1 to the equation 2x + y = 37:

2x + (4x + 1) = 37

(2x + 4x) + 1 = 37 subtract 1 from both sides

6x = 36 divide both sides by 6

x = 6

Pyt the value of x to the first equation:

y = 4(6) + 1

y = 24 + 1

y = 25

4 0

2 years ago

Pleaseeeee helpppp !!!!!!!! Will mark Brianliest !!!!!!!!!!!!!

kipiarov [429]

Answer:

so this uses proportions.

you need to find the side BF which is proportional to the side BF.

You do:

9/6=x/42

and cross multiply

9*42=6*x

378=6x

divide by 6 on both sides

x=63

the answer is 63

4 0

3 years ago

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