Please help me 4and 5

What is the circumference of a circle with a diameter of 4.2 cm?

iogann1982 [59]

Answer:

it would be C≈13.19cm

hope this helps :)

6 0

3 years ago

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7x^2=9+x what are the values of x Will give medal and points

DENIUS [597]

7x² = 9 + x Subtract x from both sides
7x² - x = 9 Subtract 9 from both sides
7x² - x - 9 = 0 Use the Quadratic Formula

a = 7 , b = -1 , c = -9

x = $\frac{-b \pm \sqrt{b^2 - 4ac} }{2a}$ Plug in the a, b, and c values
x = $\frac{- (-1) \pm \sqrt{(-1)^2 - 4(7)(-9)} }{2(7)}$ Cancel out the double negative
x = $\frac{1 \pm \sqrt{(-1)^2 - 4(7)(-9)} }{2(7)}$ Square -1
x = $\frac{1 \pm \sqrt{1 - 4(7)(-9)} }{2(7)}$ Multiply 7 and -9
x = $\frac{1 \pm \sqrt{1 - 4(-63} }{2(7)}$ Multiply -4 and -63
x = $\frac{1 \pm \sqrt{1 + 252} }{2(7)}$ Multiply 2 and 7
x = $\frac{1 \pm \sqrt{1 + 252} }{14}$ Add 1 and 252
x = $\frac{1 \pm \sqrt{253} }{14}$ Split up the $\pm$
x = $\left \{ {{ \frac{1 + \sqrt{253} }{14} } \atop { \frac{1 - \sqrt{253} }{14} }} \right.$
The approximate square root of 253 is 15.905973.
x ≈ $\left \{ { \frac{1 + 15.905973}{14} } \atop { \frac{1 - 15.905973}{14} }} \right$ Add and subtract
x ≈ $\left \{ {{ \frac{16.905973}{14} } \atop { \frac{14.905973}{14} }} \right.$ Divide
x ≈ $\left \{ {{1.2075} \atop {1.0647}} \right.$ Round to the nearest hundredth
x ≈ $\left \{ {{1.21} \atop {1.06}} \right.$

7 0

3 years ago

Karen is 6 years older than her sister Michelle, and Michelle is 2 years younger than their brother David. If the sum of their a

ale4655 [162]

$K\ \rightarrow\ the\ Karen's\ age\\M\ \rightarrow\ the\ Michelles\ age \\D\ \rightarrow\ the\ David's\ age\\\\K=M+6\\M=D-2\ \ \ \Rightarrow\ \ \ D=M+2\\K+M+D=62\\\\(M+6)+M+(M+2)=62\\3M+8=62\\3M=54\ /:3\\M=18\ \ \ \Rightarrow\ \ \ K=18+6=24\ \ \ and\ \ \ D=18+2=20\\\\Ans.\ Michelle\ is\ 18,\ David\ is\ 20,\ Karen\ is\ 24.$

6 0

3 years ago

Pulse rates of women are normally distributed with a mean of 77.5 beats per minute and a standard deviation of 11.6 beats per mi

irakobra [83]

Answer:

a) Mean=0 and Standard deviation=1

b) The z-scores have no units of measurement

Step-by-step explanation:

When we convert all the pulse rates of women to z-scores using the formula;

$z=\frac{x-\mu}{\sigma}$ the mean is 0 and the standard deviation is 1.

The reason is that, the resulting distribution of z-scores forms a normal distribution which has a mean of 0 and a standard deviation of 1.

b) The z-scores are standardize scores and has no units of measurement. They give us how many standard deviations below or above the mean of the corresponding values.

8 0

3 years ago

You can buy a box of 150 sharpie pens for $165 or a dozen for $13.50

Setler [38]

Answer: do the a dozen for $13.50

Step-by-step explanation: It will help save money

5 0

3 years ago