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Mathematics 15 Online
OpenStudy (darkbluechocobo):

Help with Law of Sines

OpenStudy (darkbluechocobo):

So i did two problems: 1.Use the Law of Sines to solve (if possible) the triangle for the value of c. Round answers to the nearest tenths. A = 27.5°, a = 15.0 cm, b = 36.4 cm I got an imaginary number when solving for B. So I answered it no solution 2.Use the Law of Sines to solve (if possible) the triangle for the value of c. Round answers to the nearest tenths. A = 135.3°, a = 14.6 m, b = 18.3 m When solving for B, I got -17 degrees. I believe that would be no solution as well.

OpenStudy (darkbluechocobo):

I don't know if that would be correct though

OpenStudy (darkbluechocobo):

@freckles

OpenStudy (darkbluechocobo):

How I set up both:|dw:1427502639896:dw|

OpenStudy (darkbluechocobo):

\[B=\sin^{-1}\frac{ 36.4\sin27.5 }{ 15 }\]

OpenStudy (darkbluechocobo):

Would that look right?

jimthompson5910 (jim_thompson5910):

Since 36.4*sin(27.5)/15 = 1.12, which is larger than 1, this means that there are no solutions to sin(B) = 1.12 and no solutions for #1

OpenStudy (darkbluechocobo):

So the second I would set up

OpenStudy (darkbluechocobo):

|dw:1427503327836:dw|

jimthompson5910 (jim_thompson5910):

#2 sin(B)/b = sin(A)/a sin(B)/18.3 = sin(135.3)/14.6 sin(B) = 18.3*sin(135.3)/14.6 sin(B) = 0.88165 B = ???

OpenStudy (darkbluechocobo):

\[B=\sin^{-1}\frac{ 18.3\sin135.3 }{ 14.6 }\]

OpenStudy (darkbluechocobo):

I thought you ahve to take arcsin for this?

jimthompson5910 (jim_thompson5910):

you do, yes

jimthompson5910 (jim_thompson5910):

what do you get for angle B?

OpenStudy (darkbluechocobo):

1.07935207?

jimthompson5910 (jim_thompson5910):

make sure you are in degree mode

OpenStudy (darkbluechocobo):

in degrees its 61.84

jimthompson5910 (jim_thompson5910):

yes

jimthompson5910 (jim_thompson5910):

what is angle C?

OpenStudy (darkbluechocobo):

180-61.84-135.3

jimthompson5910 (jim_thompson5910):

yep

OpenStudy (darkbluechocobo):

I get -17

jimthompson5910 (jim_thompson5910):

me too

jimthompson5910 (jim_thompson5910):

so this triangle isn't possible either

OpenStudy (darkbluechocobo):

So i would be right then

jimthompson5910 (jim_thompson5910):

you are

OpenStudy (darkbluechocobo):

Good I just wanted someone to confirm to make sure i wasnt going crazy

jimthompson5910 (jim_thompson5910):

"When solving for B, I got -17 degrees." I think you meant to say "for C"

OpenStudy (darkbluechocobo):

Indeed that is what i meant lol

OpenStudy (darkbluechocobo):

Thank you for checking for me :D

jimthompson5910 (jim_thompson5910):

you're welcome

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