Question

I need help finishing a problem I am almost done with it but I got stuck!!! Here is the question. Using the Law of Cosine, in triangle RST, if r=14, s=9, t= 9 find the angle of S. I am down to -151/-168=cos S but when I divide that it doesn't work out!!!

Answer 1

@hartnn can you help me?

Answer 2

how did u get -151?

Answer 3

and 168 too :P

which formula did you use? :O

Answer 4

This is what I did can you tell me if my answer is right?

Answer 5

ohhhhhh, your t= 6 ???
you put t=9 in your question

Answer 6

Ohhh opps sorry, I wasn't looking at the question when I typed it.

Answer 7

yes, your work is good
angle S is indeed 26 degrees :)

Answer 8

Thank you. I have more so when I finish them can I post them to see if they are right?

Answer 9

sure :)

Answer 10

@hartnn Is this right?

Answer 11

that is also correct :)

triangle sides are 15,28,17, right ? then yes, angle is 27 :)

Answer 12

Okay thank you, haha one more. :)

Answer 13

bring it on!

Answer 14

I need help on this one the question is Using the Law of Sine, in triangle ABC, if angle c= 135, angle b=10, side c= 45, what is the measure of a?

Answer 15

find measure of angle a, first!
know how to ?

Answer 16

C=135, B=10, A= find out

c= 45, a= required.

Answer 17

A+B+C= 180

Answer 18

dont you just add up the angles you know then subtract them from 180

Answer 19

a=25

Answer 20

i mean 35 sorry

Answer 21

yes, A =35
(sorry i lost my internet connection)

now use the sine law !
\(\huge \dfrac{a}{\sin A }=\dfrac{c}{\sin C}\)

only 'a' is unknown! :)

Answer 22

this is what i did

Answer 23

but you already know angle A .-.

you need side =a

so plug in A =35, C =135, c =45
in the sine law formula and find 'a' :)

Answer 24

I'm confused on how to do that

Answer 25

\(\huge \dfrac{a}{\sin 35}=\dfrac{45}{\sin 135}\)

Answer 26

multiply sin 35 on both sides

Answer 27

I'm a little confused

Answer 28

\(\huge \dfrac{a}{\sin 35}\times \sin 35=\dfrac{45}{\sin 135}\times \sin 35 \\ ~\\ \huge a=\dfrac{45}{\sin 135}\times \sin 35 =... \)

Answer 29

if you're still confused, use a calculator :)

Answer 30

I can't see all of the equation you posted

Answer 31

:O you can't ? ...

ok,

a/ sin 35 = 45 /sin 135

a = 45 sin 35 /sin 135

thats what i wrote!

Answer 32

ohh okay thank you

Answer 33

^_^

Answer 34

I got 34.2

Answer 35

my calculator gave me
36.5

Answer 36

http://www.wolframalpha.com/input/?i=45+sin+35+degrees+%2F+sin+135+degrees++

Answer 37

i did it wrong the first time the second time i got 36.5

Answer 38

cool! :)

Answer 39

Thank you so much!!! :)

Answer 40

welcome ^_^