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3 years ago

Given that the measurement is in centimeters, find the circumference of the circle to the nearest tenth. (Use 3.14 for π)

Mathematics

2 answers:

Leokris [45]3 years ago

8 0

Answer:
A
I I already had this question on one of my tests

marysya [2.9K]3 years ago

5 0

Answer:

Step-by-step explanation:

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I don’t understand this at all please help

Deffense [45]

Answer:

You need 10 of those numbers to be whole numbers, decimals, or fractions (THESE ARE RATIONAL)

You need the other 10 of those numbers to radicals, or numbers similar to pi (THESE ARE IRRATIONAL)

Step-by-step explanation:

4 0

3 years ago

The decay of 942 mg of an isotope is described by the function A(t)= 942e-0.012t, where t is time in years. Find the amount left

Katarina [22]

$\bf A(t)=942e^{-0.012t}\qquad \boxed{\stackrel{\textit{after 71 years}}{t=71}}\qquad \qquad A(t)=942e^{-0.012(71)}
\\\\\\
A(t)\approx 401.82042087707606813879$

4 0

3 years ago

Read 2 more answers

In triangles DEF and OPQ, ∠D ≅ ∠O, ∠F ≅ ∠Q, and segment DF ≅ segment OQ. Is this information sufficient to prove triangles DEF a

zalisa [80]

Answer:

We can't prove this with the SAS postulate.

Step-by-step explanation:

SAS means that two sides and the angle between those two sides are equal.

Side Angle Side (SAS)

That's why we can't prove this with the SAS postulate.

3 0

2 years ago

Jada makes sparkling juice by mixing 2 cups of sparkling water with every 3 cups of apple juice. How much sparkling water does J

grandymaker [24]

<h2>Answer:</h2>

<u>Answer is 10 </u>

Step-by-step explanation:

I hope this is correct!

8 0

3 years ago

Read 2 more answers

A swimming pool with a volume of 30,000 liters originally contains water that is 0.01% chlorine (i.e. it contains 0.1 mL of chlo

SpyIntel [72]

Answer:

$R_{in}=0.2\dfrac{mL}{min}$

$C(t)=\dfrac{A(t)}{30000}$

$R_{out}= \dfrac{A(t)}{1500} \dfrac{mL}{min}$

$A(t)=300+2700e^{-\dfrac{t}{1500}},$ A(0)=3000$

Step-by-step explanation:

The volume of the swimming pool = 30,000 liters

(a) Amount of chlorine initially in the tank.

It originally contains water that is 0.01% chlorine.

0.01% of 30000=3000 mL of chlorine per liter

A(0)= 3000 mL of chlorine per liter

(b) Rate at which the chlorine is entering the pool.

City water containing 0.001%(0.01 mL of chlorine per liter) chlorine is pumped into the pool at a rate of 20 liters/min.

$R_{in}=$ (concentration of chlorine in inflow)(input rate of the water)

$=(0.01\dfrac{mL}{liter}) (20\dfrac{liter}{min})\\R_{in}=0.2\dfrac{mL}{min}$

Volume of the pool =30,000 Liter

$Concentration, C(t)= \dfrac{Amount}{Volume}\\C(t)=\dfrac{A(t)}{30000}$

(d) Rate at which the chlorine is leaving the pool

$R_{out}=$ (concentration of chlorine in outflow)(output rate of the water)

$= (\dfrac{A(t)}{30000})(20\dfrac{liter}{min})\\R_{out}= \dfrac{A(t)}{1500} \dfrac{mL}{min}$

(e) Differential equation representing the rate at which the amount of sugar in the tank is changing at time t.

$\dfrac{dA}{dt}=R_{in}-R_{out}\\\dfrac{dA}{dt}=0.2- \dfrac{A(t)}{1500}$

We then solve the resulting differential equation by separation of variables.

$\dfrac{dA}{dt}+\dfrac{A}{1500}=0.2\\$The integrating factor: e^{\int \frac{1}{1500}dt} =e^{\frac{t}{1500}}\\$Multiplying by the integrating factor all through\\\dfrac{dA}{dt}e^{\frac{t}{1500}}+\dfrac{A}{1500}e^{\frac{t}{1500}}=0.2e^{\frac{t}{1500}}\\(Ae^{\frac{t}{1500}})'=0.2e^{\frac{t}{1500}}$

Taking the integral of both sides

$\int(Ae^{\frac{t}{1500}})'=\int 0.2e^{\frac{t}{1500}} dt\\Ae^{\frac{t}{1500}}=0.2*1500e^{\frac{t}{1500}}+C, $(C a constant of integration)\\Ae^{\frac{t}{1500}}=300e^{\frac{t}{1500}}+C\\$Divide all through by e^{\frac{t}{1500}}\\A(t)=300+Ce^{-\frac{t}{1500}}$

Recall that when t=0, A(t)=3000 (our initial condition)

$3000=300+Ce^{0}\\C=2700\\$Therefore:\\A(t)=300+2700e^{-\dfrac{t}{1500}}$

3 0

3 years ago