A community for students.
Here's the question you clicked on:
 0 viewing
milliex51
 3 years ago
How do I find the measure of the indicated angle, to the nearest tenth of a degree using sine law and cosine law?
milliex51
 3 years ago
How do I find the measure of the indicated angle, to the nearest tenth of a degree using sine law and cosine law?

This Question is Closed

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1337042419972:dw

jiberjiber
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1337043771132:dw

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0no, it's 104 degrees and the side length of BC is 45 m

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1Let's say that side AB is c and use the law of cosines.

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1337046422125:dw I found the side length of AC using cosine law: AC^2 = BC^2 + AB^2  2(BC)(AB)cosB = 45^2 + 20^2  2(45)(20)cos104 = 2860.459412 AC = 53.48 m

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1\[c^2=20^2+45^22(20)(45)\cos 104\]

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0and then I used cosine law again to find the side length of DC: DC^2 = BC^2 _ BD^2 2(BC)(BD)cosB = 45^2 + 30^2 2(45)(30)cos(104 degrees) = 3578.19 I used the triangle BCD

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1Now find the meassure of angle ACB using the law of sines.

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0but what angle am I suppose to find for triangle ABC, when angle B=104 degrees? wait I am confused..

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1\[\frac{\sin 104}{53.48}=\frac{\sin ACB}{20}\]

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1Angle ACB = 21.3 degrees

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0how did you get 21.3?

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0and the angle of C has to be 7.3 degrees..

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.120(sin 104)/52.48 Then hit the inverse sin button.

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0how did you get 54.7 and 21.3? :O i'm so sorry

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1Look above. It tells you how to get the 21.3. Then use the fact that the sum of the angles of a triangle is 180 to get 54.7

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0ohh yup. But how am I going to find angle C? D:

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1But you want the angle theta so try this: \[(CD)^2=30^2+45^22(30)(45)\cos 104\]

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0i'm sorry but it just says, 'math processing error..'

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1Now use the law of sines to find angle DCB. Subtract 21.3 from DCB and that will be theta.

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0okay. I'm still kind of confused but thank you so much!

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1\[\frac{\sin 104}{59.8}=\frac{\sin DCB}{30}\]

Mertsj
 3 years ago
Best ResponseYou've already chosen the best response.1What are you confused about?

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0Mertsj, how come the answer at the back fo my book is 7.8 degrees? o.o

milliex51
 3 years ago
Best ResponseYou've already chosen the best response.0ohh, never mind :$ THANK YOU!!
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.