How do you find the cosine of an angle when the angle measure is not given
Well, it depends what sides or angles are given.
If you're finding cosine of an angle, you would first have to figure out the type of triangle you are dealing with in order to find the unknown angle or theta.
If your triangle is a right triangle and you're trying to find another angle, you would use SOHCAHTOA. Cosine would be used if you have the adjacent and hypotenuse sides.
If your triangle is not a right triangle, use cosine law. For example, if you are trying to find angle A, you would use the first formula, and the second formula for angle B and third for angle C.
cos(A) = b2 + c2 − a2 / 2bc
cos(B) = c2 + a2 − b2 / 2ca
cos(C) = a2 + b2 − c2 / 2ab
I hope this answered your question LOL or if you understood any of it. I literally just finished grade 10 math last week and I'm pretty sure I did this right but you could check ofc. I recommend www.mathsisfun.com if you need more help!
Have a great evening and good luck!
Sara
