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milliex51
Group Title
How do I find the measure of the indicated angle, to the nearest tenth of a degree using sine law and cosine law?
 2 years ago
 2 years ago
milliex51 Group Title
How do I find the measure of the indicated angle, to the nearest tenth of a degree using sine law and cosine law?
 2 years ago
 2 years ago

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milliex51 Group TitleBest ResponseYou've already chosen the best response.0
dw:1337042419972:dw
 2 years ago

jiberjiber Group TitleBest ResponseYou've already chosen the best response.0
Uh, what?
 2 years ago

jiberjiber Group TitleBest ResponseYou've already chosen the best response.0
dw:1337043771132:dw
 2 years ago

jiberjiber Group TitleBest ResponseYou've already chosen the best response.0
four degrees?
 2 years ago

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337046316750:dw
 2 years ago

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

milliex51 Group TitleBest ResponseYou've already chosen the best response.0
dw: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
 2 years ago

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

milliex51 Group TitleBest ResponseYou've already chosen the best response.0
and 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
 2 years ago

milliex51 Group TitleBest ResponseYou've already chosen the best response.0
and now I am stuck..
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337046557115:dw
 2 years ago

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337046713091:dw
 2 years ago

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

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
Angle ACB = 21.3 degrees
 2 years ago

milliex51 Group TitleBest ResponseYou've already chosen the best response.0
how did you get 21.3?
 2 years ago

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337046878417:dw
 2 years ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
20(sin 104)/52.48 Then hit the inverse sin button.
 2 years ago

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
Look 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
 2 years ago

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

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337047600966:dw
 2 years ago

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
dw:1337047693118:dw
 2 years ago

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

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

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

Mertsj Group TitleBest ResponseYou've already chosen the best response.1
What are you confused about?
 2 years ago

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

milliex51 Group TitleBest ResponseYou've already chosen the best response.0
ohh, never mind :$ THANK YOU!!
 2 years ago
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