Ask your own question, for FREE!
Mathematics 11 Online
OpenStudy (cookiimonster627):

solve each triangle. if there are two triangles solve them both. A= 9 degrees 52' a= 3761ft b=5293ft

OpenStudy (cookiimonster627):

@jim_thompson5910

jimthompson5910 (jim_thompson5910):

|dw:1460072914426:dw|

jimthompson5910 (jim_thompson5910):

|dw:1460072943762:dw|

jimthompson5910 (jim_thompson5910):

9 degrees, 52 arcminutes = 9+(52/60) = 9.86667 degrees approx |dw:1460073034806:dw|

jimthompson5910 (jim_thompson5910):

to find x, you'll need to use the law of cosines. Are you familiar with that formula?

OpenStudy (cookiimonster627):

sin9.8667/x = sin a/ 3761

jimthompson5910 (jim_thompson5910):

no you're thinking of the law of sines

OpenStudy (cookiimonster627):

whats law of cosine then

jimthompson5910 (jim_thompson5910):

the law of sines cannot be used yet. We need to figure out x first actually now that I think about it, we can use the law of sines to find angle B

OpenStudy (cookiimonster627):

how do we do that?

jimthompson5910 (jim_thompson5910):

let's use the law of sines to find angle B \[\Large \frac{\sin(B)}{b} = \frac{\sin(A)}{a}\] \[\Large \frac{\sin(B)}{5293} = \frac{\sin(9.86667)}{3761}\] does that help at all?

OpenStudy (cookiimonster627):

0.645

jimthompson5910 (jim_thompson5910):

how are you getting that?

OpenStudy (cookiimonster627):

i plugged that equation into the calculator

jimthompson5910 (jim_thompson5910):

\[\large \frac{\sin(B)}{5293} = \frac{\sin(9.86667^{\circ})}{3761}\] \[\large 3761*\sin(B) = 5293*\sin(9.86667^{\circ})\] \[\large \sin(B) = \frac{5293*\sin(9.86667^{\circ})}{3761}\] \[\large \sin(B) \approx 0.2411559\] \[\large B \approx \arcsin(0.2411559) \ \text{ or } \ B \approx 180-\arcsin(0.2411559)\] \[\large B \approx 13.95477255^{\circ} \ \text{ or } \ B \approx 166.045227^{\circ}\] Let me know if you have any questions on how I got those values for B

OpenStudy (cookiimonster627):

i understand that makes sence

jimthompson5910 (jim_thompson5910):

If B is approximately 13.95477255 degrees, then what is the value of angle C?

OpenStudy (cookiimonster627):

is it 180-13.955? if it is then i got 166.045

jimthompson5910 (jim_thompson5910):

don't forget about angle A

jimthompson5910 (jim_thompson5910):

A+B+C = 180 degrees

OpenStudy (cookiimonster627):

156.178

jimthompson5910 (jim_thompson5910):

180-13.95477255-9.86666666666667 = 156.178560783333 looks good

jimthompson5910 (jim_thompson5910):

If B is approximately 166.045227 degrees, then what is the value of angle C?

OpenStudy (cookiimonster627):

i thought b was 13.955

jimthompson5910 (jim_thompson5910):

B is two possible angles (we're in the SSA case)

OpenStudy (cookiimonster627):

ohhh okay sorry i was confused

jimthompson5910 (jim_thompson5910):

eg: sin(30) = 1/2 sin(150) = 1/2 so if you had sin(x) = 1/2 then x = 30 or 150 degrees

OpenStudy (cookiimonster627):

oh ok

jimthompson5910 (jim_thompson5910):

If B is approximately 166.045227 degrees, then what is the value of angle C?

OpenStudy (cookiimonster627):

13.955?

jimthompson5910 (jim_thompson5910):

If B is approximately 166.045227 degrees, then what is the value of angle C? C = 180-A-B C = 180-9.86666666666667-166.045227 C = 4.08810633333331

jimthompson5910 (jim_thompson5910):

agreed?

OpenStudy (cookiimonster627):

yes

jimthompson5910 (jim_thompson5910):

So we have 2 possible triangles we can form here Triangle 1 A = 9.86666666666667 degrees B = 13.95477255 degrees C = 156.178560783333 degrees Triangle 2 A = 9.86666666666667 degrees B = 166.045227 degrees C = 4.08810633333331 degrees Angle A stays the same both times all three angles (for either triangle) are approximate

jimthompson5910 (jim_thompson5910):

let me know when you're ready for the next part

OpenStudy (cookiimonster627):

im ready

jimthompson5910 (jim_thompson5910):

For now, let's just focus on Triangle 1 A = 9.86666666666667 degrees B = 13.95477255 degrees C = 156.178560783333 degrees

OpenStudy (cookiimonster627):

okay

jimthompson5910 (jim_thompson5910):

using these values, are you able to find x in the drawing? |dw:1460075042730:dw|

OpenStudy (cookiimonster627):

i think so but im not sure how to

jimthompson5910 (jim_thompson5910):

you'll use the law of sines \[\Large \frac{\sin(C)}{c} = \frac{\sin(A)}{a}\] \[\Large \frac{\sin(156.17856^{\circ})}{c} = \frac{\sin( 9.8667^{\circ})}{3761}\] I'll let you solve for c

OpenStudy (cookiimonster627):

7301.260

jimthompson5910 (jim_thompson5910):

incorrect. Try again

OpenStudy (cookiimonster627):

-3549.478

jimthompson5910 (jim_thompson5910):

\[\Large \frac{\sin(C)}{c} = \frac{\sin(A)}{a}\] \[\Large \frac{\sin(156.17856^{\circ})}{c} = \frac{\sin( 9.8667^{\circ})}{3761}\] \[\Large 3761*\sin(156.17856^{\circ}) = c*\sin( 9.8667^{\circ})\] \[\Large \frac{3761*\sin(156.17856^{\circ})}{\sin( 9.8667^{\circ})} = c\] \[\Large c = \ ???\]

OpenStudy (cookiimonster627):

8864.263

jimthompson5910 (jim_thompson5910):

I'm getting 8,864.68360894793

OpenStudy (cookiimonster627):

hmm i wonder why

jimthompson5910 (jim_thompson5910):

so... Triangle 1 A = 9.86666666666667 degrees B = 13.95477255 degrees C = 156.178560783333 degrees a = 3761 b = 5293 c = 8,864.68360894793

jimthompson5910 (jim_thompson5910):

there may be rounding error somewhere

OpenStudy (cookiimonster627):

probably

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!