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Ksenya-84 [330]
2 years ago
14

What is the area of a circle with a diameter of 21 centimeters? use 3.14 for pi

Mathematics
2 answers:
Pavel [41]2 years ago
7 0

Answer:

346.185 cm²

Step-by-step explanation:

radius = diameter / 2

Area of a circle = πr²

radius = 21/2 = 10.5

Area = 3.14(10.5)²

Area = 346.185 cm²

Phantasy [73]2 years ago
4 0

Answer:

346.4 square centimeters (cm²)

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95% confidence level

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a. If a 95% confidence interval with a margin of error of no more than 0.04 is desired, give a close estimate of the minimum sample size that will guarantee that the desired margin of error is achieved. (Remember to round up any result, if necessary.)

This is n for which M = 0.04. So

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b. If a 95% confidence interval with a margin of error of no more than 0.02 is desired, give a close estimate of the minimum sample size necessary to achieve the desired margin of error.

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(\sqrt{n})^2 = (\frac{1.96*0.5}{0.02})^2

n = 2401

The minimum sample size is 2401.

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