All categories

4 years ago

What is 690 as a decimal

Mathematics

1 answer:

Darya [45]4 years ago

7 0

The decimal to 690 it’s going to be 6.9

You might be interested in

Solve x^2 = 64, where x is a real number.

abruzzese [7]

Answer: x=8

Step-by-step explanation:

8×8=64

4 0

4 years ago

Read 2 more answers

Element X decays radioactively with a half life of 11 minutes. If there are 870 grams of Element X, how long, to the nearest ten

serg [7]

Answer:

It would take 27.5 minutes the element to decay to 154 grams.

Step-by-step explanation:

The decay equation:

$\frac {dN}{dt}\propto -N$

$\Rightarrow \R\frac {dN}{dt}=-\lambda N$

$\Rightarrow \frac {dN}N=-\lambda dt$

Integrating both sides

$\Rightarrow \int \frac {dN}N=\int-\lambda dt$

$\Rightarrow ln|N|=-\lambda t+c$

When t=0, N= $N_0$ = initial amount

$ln|N_0|=-\lambda .0+c$

$\Rightarrow c=ln|N_0|$

$ln|N|=-\lambda t+ln|N_0|$

$\Rightarrow ln|N|-ln|N_0|=-\lambda t$

$\Rightarrow ln|\frac{N}{N_0}|=-\lambda t$

Decay equation:

$ln|\frac{N}{N_0}|=-\lambda t$

Given that, the half life of of element X is 11 minutes.

For half life, $N=\frac12 N_0$ , t= 11 min.

$ln|\frac{N}{N_0}|=-\lambda t$

$\Rightarrow ln|\frac{\frac12N_0}{N_0}|=-\lambda . 11$

$\Rightarrow ln|\frac12}|=-\lambda . 11$

$\Rightarrow -\lambda . 11=ln|\frac12}|$

$\Rightarrow \lambda =\frac{ln|\frac12|}{-11}$

$\Rightarrow \lambda =\frac{ln|2|}{11}$ [ $ln|\frac12|=ln|1|-ln|2|=-ln|2|$ , since ln|1|=0]

N=154 grams, $N_0$ = 870 grams, t=?

$ln|\frac{N}{N_0}|=-\lambda t$

$\Rightarrow ln|\frac{154}{870}|=-\frac{ln|2|}{11}.t$

$\Rightarrow t= \frac{ln|\frac{154}{870}|\times 11}{-ln|2|}$

=27.5 minutes

It would take 27.5 minutes the element to decay to 154 grams.

5 0

3 years ago

Please someone answer. Identify the vocabulary word that matches the picture.

miss Akunina [59]

Answer:

alternate interior angles

Step-by-step explanation:

The angles are alternate interior angles

They are between the parallel lines and on opposite sides of the transversal

5 0

3 years ago

6.5 + m = 17 <br><br> solve for m

Hunter-Best [27]

Answer:

m=10.5

Step-by-step explanation:

For this equation you could do the long or simple way, I will be using the easier way, you can take the 17 and 6.5, subtract the 17 by the 6.5 and you get 10.5.

m=10.5

I hope that this has helped you, have an great day.

3 0

3 years ago

Read 2 more answers

Please I need the answer!!! What is the circumference of the circle?

S_A_V [24]

Answer:

the formula for the circumference of a circle is c=2pi(R)

Step-by-step explanation:

in this case that would be 2(3.14)(6). that would equal 37.68. your circumference is 37.68 cm. hope i helped :)

3 0

3 years ago

Read 2 more answers