Find the value of x. If your answer is not an integer, leave it in simplest radical form. The diagram is not drawn to scale.

Question

anonymous · Answer

attachment

opcode · Answer

Okay. So do we use tangent/sine/cosine?

anonymous · Answer

honestly i dont know

opcode · Answer

Do you know what tangent/sine/cosine are?

anonymous · Answer

i know they are used in trigonometry

opcode · Answer

Okay...
But do you know what tangent/sine/cosine do? And what they mean?

anonymous · Answer

no...

opcode · Answer

Then why did you teacher assign this question O.o?

anonymous · Answer

tbh i have no clue im in geometry and they give trig questions... O.o

opcode · Answer

There doing for preparing you for whatever class you have next... 
Anyway in this case you use Cosine.
In geometry you learn of "special" triangle.
More specifically 60/90 triangles.
So:
$cos(60) = x/10 $ 
Because of SOH-CAH-TOA.
s = o/h
c = a/h
t = o/a
Plug cos(60) into your calculator = 1/2
So:
1/2 = x/10
Cross multiple that.

opcode · Answer

$\huge \frac {1}{2} = \frac {x}{10}$
2x = 10
Divide each side by 2.
10/2 = 5
2x/2 = x
x = 5

anonymous · Answer

ok what does cosine mean though

opcode · Answer

Check your answer: http://bit.ly/Yy924K Wolframalpha says it's right :)

opcode · Answer

Errm. 
Ask you teacher?
She could explain it :3

anonymous · Answer

ok ill ask thank youi for the help

opcode · Answer

No problem :)