Answer: Cos, Cosine
Step-by-step explanation:
You can use SOH CAH TOA to help you find out whether you are using Sine, Cosine or Tangent.
SOH- The 'S' is for Sine, then the 'O' and the 'H' is for Opposite over Hypotenuse.
CAH- The 'C' is for Cosine, the 'A' and the 'H' is for Adjacent over Hypotenuse.
TOA- The 'T' is for Tangent, then the 'O' and the 'A' is for Opposite over Adjacent.
As you have the Adjacent (the side next to the angle you are looking for) and Hypotenuse (the side opposite the right angle), you would be using Cosine.
I haven't answered it because I read this as though you wanted the explanation. If you do want an answer just let me know then I can edit my answer.
Hope this helps :)
