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2 years ago

Elijah calculated the area of a circle to be 900π units². Which of the following was the radius of the circle?

Mathematics

1 answer:

scZoUnD [109]2 years ago

7 0

Answer: A. 30

Step-by-step explanation:

The formula for the area of a circle is pi*r^2, where r is the radius of the circle.

900pi = pi*r^2

Divide both sides by pi.

900 = r^2

Square root both sides.

r = +/- 30.

Since the radius cannot be negative, the answer is 30 units.

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Sixty miles per hour is how many feet per second

dybincka [34]

5280 feet = 1 mile

5280 × 60 = 316800

316800 feet per hour

3600 seconds = 1 hour

316800 feet per 3600 seconds

316800 ÷ 3600 = 88

88 feet per second

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2 years ago

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A random sample of 40 college students has a mean earnings of $3120 over the summer months. Assume the population standard devi

PSYCHO15rus [73]

Answer:

A normal distribution or z-test is used to construct a confidence interval.

Step-by-step explanation:

We are given the following in the question:

Sample mean, $\bar{x}$ = $3120

Sample size, n = 40

Population standard deviation, σ = $677

The distribution of earnings of college is a normal distribution.

Conditions:

Since we are given the population standard deviation and the the sample size is also greater than 30.

Conclusion:

Thus, we use a normal distribution or z-test to construct a confidence interval.

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3 years ago

How do I do this? it doesn't make sense.

yuradex [85]

I think you subtitute de 34 by x not sure

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3 years ago

-3(5n-8)=-8(n-3)<br><br> Please Hurry

BartSMP [9]

Answer:

$- 3(5n - 8) = - 8(n - 3)$

$- 15n + 24 = -8 n + 24$

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2 years ago

Sales tax on an item is directly proportional to the cost of the item purchased. If the tax on a $500 item is $30, what is the s

Archy [21]

30 / 500 = x / 900....$ 30 tax / 500 item = $ x tax on 900 item
cross multiply
(500)(x) = (900)(30)
500x = 27000
x = 27000/500
x = 54 <===

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3 years ago

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