Question

Help here please: Are my answers correct?.

b. Determine the measure of ∠ B if it exists.

Answer:
Using sine law for this q.
sinB/7.2 = sin(35)/9.3
sin B = 7.2 * sin35/9.3 = 0.472
Angle(B) = sin-1(0.472) = 28.19
Therefore, Angle B = 28.19

Answer 1

I already answer it, I just need to check whether my answers are correct

Answer 2

@callisto:) hello again! Are they correct? I used formulas from my book

Answer 3

I'm not sure you've used the sine rule correctly here

Answer 4

a, correct
b,i don't think so
sinB/b = sin(A)/a
sinB/9.3 = sin(35)/7.2 ....

Answer 5

\[\frac{9.3}{\sin(B)}=\frac{7.2}{\sin(35)}\]

Answer 6

Now that callisto mentions it, I agree. My bad. :(

Answer 7

Oh!, i got the orders mixed up. One sec, Il retry

Answer 8

Not really....

Answer 9

No?

Answer 10

ok. Il review it one sec

Answer 11

hmmm - I get a different answer.
and remember there should be two values - one acute and one obtuse

Answer 12

sinB = 9.3sin(35)/7.2 ....

Answer 13

OMG

Answer 14

I didnt add the ) to close it in my calculator thats why it mixed it up

Answer 15

I blame the fact that you're hanging up-side-down for that ;-)

Answer 16

lol

Answer 17

ok. so is the answer then 47.79?

Answer 18

close enough :)

Answer 19

its not?

Answer 20

and the obtuse angle?

Answer 21

I've got 47.81 for the first angle. Remember you've the second possible angle

Answer 22

I got same as Callisto

Answer 23

maybe i should have added more decimals:(. whats the formula for the obstute?

Answer 24

sin(x) = sin(180-x)

Answer 25

ok so: is it 32.99?

Answer 26

the second angle is in quadrant II ....

Answer 27

no....

Answer 28

it should be greater than 90 degrees... it's an obtuse angle~

Answer 29

Ok one second:)

Answer 30

you calculated sin(B) = 0.741...
so when you take the inverse of this, you get two possible angles: x and 180-x

Answer 31

because sin(x) = sin(180-x)

Answer 32

what is the value of x?

Answer 33

so call one angle x and the other one y and we have:
y = 180 - x
with:
sin(x) = sin(y) = 0.741...

Answer 34

x is the angle you've just found

Answer 35

x=B in this case

Answer 36

so is it then: 0.129?

Answer 37

so its 7.41?

Answer 38

ok - slow down
you understand the steps up to:

sin(B) = 0.741...

Answer 39

oh boy, this part im confused

Answer 40

sinB = 9.3sin(35)/7.2 = 0.741...

agreed?

Answer 41

Yes Agreed:)

Answer 42

ok, when you invert this to find B, you do:

B = arcsin(0.741...)

agreed?

Answer 43

Agreed

Answer 44

that has many possible answers.
but we are only interested in the first two quadrants.
so the solutions are:

B = 47.81 and (180 - 47.81)

Answer 45

understand?

Answer 46

yes:)

Answer 47

phew! - we finally got there... :D

Answer 48

:) THank you so much. sorry, Sometimes im really slow XD. Thank you for being patient and helping me:)

Answer 49

don't worry - at least you persevere which means you are learning.
we've all been there!

Answer 50

^agree :)