# Soh Cah Toa?

havechanged
I understand that Sin is Opposite over the Hypotenuse, Cosine is Adjacent over Hypotenue, and Tangent is Opposite over the Adjacent. But I don't know how to use it. Sin has its own equation, as does Tangent...I am just confused. What do I do to find a specific angle? What about a certain side?

Thanks!

P.S I have done Soh Cah Toa during previous school years, but I never understood!

## Answers and Replies

Homework Helper
Then all I can recommend is that you draw a right triangle, label the sides and angles, stare at it for a while and THINK!

It might help if you specified on your triangle, which angle you are talking about "sin is opposite over hypotenuse" is non-sense until you specify the angle! Never say "sin". It is always sin OF A PARTICULAR ANGLE.

havechanged
Ok....here could be an example:

One angle of a right triangle is 20 degress. The length of the hypotenuse is 6 cm. How would I get the other two sides?

For the opposite side, would it be something like Sin20 is x/6?

It just doesn't make sense...What about the whole Sin is the square root of a plus b times a and b or something like that?

Thanks!

Staff Emeritus
Gold Member
So you have

x= 6* Sin20 for the opposite side,

the adjacent side would be

y = 6* Cos20

I am not sure what your last comment is about, are you refering to the Pythagorean Theorm.

a2+ b2= c2?

havechanged
Thanks for the reply.

No, it wasn't the pathagorem theorum. I don't know what it was.

Thanks again!

Homework Helper
"What about the whole Sin is the square root of a plus b times a and b or something like that? "

Now THAT'S the part that doesn't make sense! I recommend you erase that from your mind immediately!

havechanged
Ok, I will. If I do find out what I was thinking of, I'll post it!

TIMMYTANK
pay attention in class

your thinkin of 30 60 90 triangles. thats where the side across from the right angle ( hypotenuse) equals 2x. the side across from the 30 degree angle equals x and the side across from the 60 degree angle is x times the squareroot of 3