Question

Given a triangle with a = 19, A = 43°, and B = 26°, what is the length of c? Round to the nearest tenth.

I know that the final angle will be 21. But I don't know how I can find the side with just one side and 3 angles.

Answer 1

the law of sines is your best bet.

Answer 2

I'd need 2 sides to use the law of sines though :l

Answer 3

Well, you have two angles and three add to 180, so find the missing angle first. Then use law of sines.

Answer 4

43 + 26 + C = 180

Answer 5

opps okai I added up to 90 for some reason >_<

Answer 6

Okay, so @you-me-at-six, the correct value for C is...?

Answer 7

I'm talking about the angle

Answer 8

111?

Answer 9

Okay, good. Now use law of sines

Answer 10

I'm not sure how to apply it ._. (I learn all my stuff off of Youtube)

Answer 11

Nevermind I tihnk I got....

Answer 12

Let me know what you get

Answer 13

If you show your working, we can check you're using the law of sines correctly.

\[\frac{ \sin A }{a } = \frac{ \sin B }{b} = \frac{ \sin C }{c }\]



Or you could look at this... but i felt like making a drawing, isn't it pretty?
http://www.mathwarehouse.com/trigonometry/law-of-sines/images/formula-picture-law-of-sines2.png

Answer 14

I get the feeling she may not get it the first time .

Answer 15

But we'll see

Answer 16

@you-me-at-six drawing a picture might help you, label the sides/angles as in that drawing.

Answer 17

I've been doing like different versions of this problem, but what I got was roughly 26 for length c

Answer 18

Brilliantly done

Answer 19

Correct :)

Answer 20

Thank you.

Answer 21

You're welcome. Especially for the pretty drawing.

Answer 22

haha yes