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2 years ago

If the diameter of a circle is 9 cm, then its circumference is 56.52 cm. True or false?

Mathematics

1 answer:

Brrunno [24]2 years ago

3 0

Circumference
2*pi*r
2*(22/7)*(9/2)
2*(11/7)*9
198 / 7
28.28 cm

so 56.52 is not correct

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Bess [88]

Answer: 68.75

Step-by-step explanation: I did the math myself so it may not be correct, but it's at least very close.

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1 year ago

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In a survey of 2957 adults, 1455 say hey have started paying bills online in the least year construct a 99% confidence interval

Vikki [24]

Answer: 0.49 ± 0.0237

Step-by-step explanation: A interval of a 99% confidence interval for the population proportion can be found by:

$p_{hat}$ ± z. $\sqrt{\frac{p_{hat}(1-p_{hat})}{n} }$

$p_{hat}$ is the proportion:

$p_{hat}$ = $\frac{1455}{2957}$

$p_{hat}$ = 0.49

For a 99% confidence interval, z = 2.576:

0.49 ± 2.576. $\sqrt{\frac{0.49(1-0.49)}{2957} }$

0.49 ± 2.576. $\sqrt{\frac{0.49*0.51}{2957} }$

0.49 ± 2.576.(0.0092)

0.49 ± 0.0237

For a <u>99% confidence interval</u>, the proportion will be between 0.4663 and 0.5137 or 0.49 ± 0.0237

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2 years ago

The quadratic equation 2x^2+4x-30=0 has two solutions. one of the solutions is x=3 the other solution is?

BartSMP [9]

Answer:

2x^2+4x-30=0

Step-by-step explanation:

2x^2+10x-6x-30=0

2x(x+5)-6(x+5)=0

(2x-6)(x+5)=0

2x-6=0 x+5=0

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2 years ago

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nikklg [1K]

Answer:

$\frac{-117}{10}$

Step-by-step explanation:

1) Change the mixed fractions into improper fractions:

$-3\frac{1}{5} + (-8\frac{1}{2} )\\= \frac{-16}{5} - \frac{17}{2}$

2) Multiply the first fraction by 2/2 and the second fraction by 5/5 in order to create common factors on the denominator (You can do this because you are essentially multiplying by one, for example 2/2 = 1):

$\frac{-16}{5} *\frac{2}{2} - \frac{-17}{2} * \frac{5}{5} \\ =\frac{-32}{10} - \frac{85}{10}$

3) Simplify the numerator(top part) while keeping the denominator(bottom part) the same:

$\frac{-32}{10} -\frac{85}{10} \\\\=\frac{-32 - 85}{10}\\ \\= \frac{-117}{10}$

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2 years ago

Please help me! I think this 20 character thing is unnecessary when you have an attachment

PIT_PIT [208]

Answer:

Step-by-step explanation:

Also the answer must be under 9 so that rules out option D

Because We know CE = 2 and AD is visibly larger than CE, 6We can rule out option A

And that brings us down to B and C

CB is equal to 6, And I'm no genius, but I'm pretty sure AD is DEFINATLY not equal to 6.

so the answer is B

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