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3 years ago

The circumference of a circle is 3.14 inches. What is the area of the circle?

Mathematics

1 answer:

SVETLANKA909090 [29]3 years ago

6 0

Answer:

A = .785 inches ^2

Step-by-step explanation:

C = pi *d

We know the diameter = 2*r

C = pi*2*r

Substituting pi = 3.14 we can solve for r

3.14 = 2*pi*r

3.14 = 2*3.14 *r

Divide by 3.14 on each side

3.14/3.14 = 2*3.14 *r/3.14

1 = 2r

Divide by 2

1/2 =2r/2

1/2 =r

Now we can find the area

A = pi *r^2

A = 3.14 *(1/2)^2

A= 3.14 *1/4

A = .785 inches ^2

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You put $500 into an account and left it alone for three years earning simple interest. At the end of three years, you withdrew

OLga [1]

Answer:

that would mean 15$ a year

1.25$ a month

Step-by-step explanation:

hope it helped

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3 years ago

Iodine-125 has a daily decay rate of about 1%. How many milligrams of a 500 mg sample will remain after 300 days? Round the answ

Amanda [17]

So.. in this case, the starting amount is the 500mg sample... and the rate of decay, negative rate, is 1%, and at the time, the elapsed days is 0, to t = 0, P = 400

$\bf \qquad \textit{Amount for Exponential change}\\\\
A=P(1\pm r)^t\qquad 
\begin{cases}
A=\textit{accumulated amount}\\
P=\textit{starting amount}\to &500\\
r=rate\to 1\%\to \frac{1}{100}\to &0.01\\
t=\textit{elapsed period}\to &300\\
\end{cases}
\\\\\\
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7 0

2 years ago

Read 2 more answers

Find the constant rate of change for each linear function and interpret its meaning

Marina CMI [18]

the slope goes by several names

• average rate of change

• rate of change

• deltaY over deltaX

• Δy over Δx

• rise over run

• gradient

• constant of proportionality

however, is the same cat wearing different costumes.

and to get it, we simply need two points off of the straight line, hmm let's use the ones in the picture below.

$(\stackrel{x_1}{2}~,~\stackrel{y_1}{4})\qquad (\stackrel{x_2}{6}~,~\stackrel{y_2}{6}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{6}-\stackrel{y1}{4}}}{\underset{run} {\underset{x_2}{6}-\underset{x_1}{2}}}\implies \cfrac{2}{4}\implies \cfrac{1}{2}$

3 0

2 years ago

"a pollster wishes to estimate the number of left-handed scientists. how large of a sample is needed in order to be 98% confiden

nadezda [96]

The sample size should be 250.

Our margin of error is 4%, or 0.04. We use the formula

$\text{ME}=z\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide both sides by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99

Using a z-table (http://www.z-table.com) we see that this value has a z-score of approximately 2.33. Using this, our margin of error and our proportion, we have:

$0.04=2.33\sqrt{\frac{0.08(1-0.08)}{n}}
\\
\\0.04=2.33\sqrt{\frac{0.08(0.92)}{n}}$

Divide both sides by 2.33:
$\frac{0.04}{2.33}=\sqrt{\frac{0.08(0.92)}{n}}$

Square both sides:
$(\frac{0.04}{2.33})^2=\frac{0.08(0.92)}{n}$

Multiply both sides by n:
$(\frac{0.04}{2.33})^2n=0.08(0.92)$

Divide both sides to isolate n:
$\frac{0.08(0.92)}{(\frac{0.04}{2.33})^2}=n
\\
\\249.73=n
\\n\approx 250$

4 0

3 years ago

Ms. Alders has $50 to buy prizes for the treasure box in her classroom. She bought 12 packages of stickers, 8 boxes of pencils,

IceJOKER [234]

The answer is $10

if you add up the total price for each of the items it totals to $40, she has $50 so $50-$40=$10

6 0

2 years ago