Question

1. The half-life of a radioactive substance is 5 minutes. how much of an original mass of 100 grams remains after half an hour?
2. What is the area of triangle ABC if a=11, b=13 and c=31 degrees 10
3.Two sides of a triangular plot of land have the lengths of 400 ft and 600 ft. The measurement of the angle between those sides is 46 degrees 20.Find the perimeter of the plot.

Answer 1

plzzzz
help me

Answer 2

i don't know the formula?

Answer 3

\[1.\ N(t)=N _{0}e^{kt}\]\[N_{0}=100 \ g\]

Answer 4

t = 1/2 hour
k = 5/60 hour = 1 / 12 hour

Answer 5

It is a decay problem so I think you would use k = -/12 hour

Answer 6

-12?

Answer 7

k=-12?

Answer 8

I am a bit confused on the wording in 2 and 3. Can you double check and make sure they are accurate? Also, - 1 / 12 hour. I am still reviewing half-lifes to make sure I give you the correct solution.

Answer 9

why is it 1/2 from 5/60
it is half an hour so 30 minutes. . .
why do you use 60? please explain. . .

Answer 10

\[ Halflife = \frac {-ln(2)}{k} \]\[k=rate \ of \ decay\]\[ Halflife =30 \ min\]\[ 30 \ min = \frac{-ln2}{k} \]\[ k = \frac{-ln2}{30\ min} \]\[ t =5\ min \]

Answer 11

hmhm ok. .
can we proceed to the second question

Answer 12

\[N_{0}=x \]\[ N = 100\ g\]\[k=\frac{-ln2}{30\ min}\]\[t=5\ min\]

\[x = 100e^{5\frac{-ln2}{30}} \]\[x=89\ g\]I wouldn't mind getting a second take on this answer

Answer 13

I would like to do 2 and 3, but they still seem off.

Answer 14

c=31degrees10

Answer 15

Hmm, that still confuses me. Is this the correct visualisation for 3?

Answer 16

then. . .

Answer 17

that is 46 degrees 10

Answer 18

46°10 does not make sense...

Answer 19

ok

Answer 20

how to solve it
what will we use ? trigonometric functions

Answer 21

We could use trigonometry if we know it is a right triangle. The problem descriptions still seem incomplete.

Answer 22

Law of Sine or Law of Cosines? are these topics you have recently covered in lecture?

Answer 23

a little bit

Answer 24

hhhhhhhhhhhhheeeeeeeeeeeeeellllllllllppppppppp

Answer 25

I really do not think we will be able to help you. I repeat, problems 2 and 3 simply do not make sense. The metrics provided are incoherent.

Answer 26

What class title is this? High school, college?

Answer 27

higgh school

Answer 28

Algebra I/II/pre, ... Precalculus...

Answer 29

pre

Answer 30

stamp?

Answer 31

Are these problems coming from a textbook, a worksheet, or some other source

Answer 32

Its for National Achievement Test

Answer 33

Retype Problem 2. Just problem 2. Nothing else except Problem 2, word for word.

Answer 34

What is the area of \[\Delta ABC\]

Answer 35

if a=11, b=13 and C=31DEGREES 10

Answer 36

\[31^{\sigma}10\]