Question

Find the missing angles

Confused!

Diagram below

Answer 1

Are you going to post the diagram?

Answer 2

do you have any angle measurements? or is that all you have?

Answer 3

I'm confused, because I used the formlua (I believe)
and got

68.515469997 for C

then when I went to solve for b I keep getting a negative number

Answer 4

That's all I have ^

Answer 5

can you put a b and c on the correct angles? and tell me what formula you used?

Answer 6

Yes I can

Answer 7

I am not a big fan of this but maybe this can help http://www.teacherschoice.com.au/maths_library/trigonometry/solve_trig_sss.htm

Have you ever heard of SSS

Answer 8

You have to use the Law of Cosines to find the measurements of 2 angles, you know that, correct? And you got the two numbers you said above?

Answer 9

Yeah I used law of cosines to find 68.515469997

But then when solving b I keep getting a negative RAD which translates to a -angle

Answer 10

hmm

Answer 11

gimme a sec

Answer 12

\(\bf \textit{Law of Cosines}\\ \quad \\
c^2 = {\color{blue}{ a}}^2+{\color{red}{ b}}^2-(2{\color{blue}{ a}}{\color{red}{ b}})cos(C)\implies
c = \sqrt{{\color{blue}{ a}}^2+{\color{red}{ b}}^2-(2{\color{blue}{ a}}{\color{red}{ b}})cos(C)}\\ \quad \\

\cfrac{{\color{blue}{ a}}^2+{\color{red}{ b}}^2-c^2}{2{\color{blue}{ a}}{\color{red}{ b}}}=cos(C)\implies cos^{-1}\left(\cfrac{{\color{blue}{ a}}^2+{\color{red}{ b}}^2-c^2}{2{\color{blue}{ a}}{\color{red}{ b}}}\right)=\measuredangle C
\\ \quad \\
thus
\\ \quad \\
cos^{-1}\left(\cfrac{{\color{blue}{ 0.2}}^2+{\color{red}{ 0.6}}^2-0.75^2}{2{\color{blue}{ (0.2)}}{\color{red}{ (0.6)}}}\right)=\measuredangle C

\\ \quad \\


cos^{-1}\left(\cfrac{{\color{blue}{ 0.2}}^2+0.75^2-{\color{red}{ 0.6}}^2}{2{\color{blue}{ (0.2)}}(0.75)}\right)=\measuredangle B\)

Answer 13

Oh I messed up on the second angle ahh.

Answer 14

@jdoe0001 What's the formula for finding angle a?

Answer 15

For b I got 35.134655 degrees

Answer 16

these decimals are a pain, get rid of them !!

Answer 17

not only in the question, but in the answer
no one wants an answer in degrees with 6 decimal points!
we can do it if you are still there, using the law of cosines for one step, the law of sines for the rest

Answer 18

I'm still here, sorry I just always use decimals :(!

Answer 19

@satellite73