Answer: The answer is 33.69!
Step-by-step explanation: When performing trigonometric problems it is important to pay attention to all of your sides even when you are finding a missing angle. The sides will show you which of the sides to divide over the other, and which equations to perform. In this case the number 6 is opposite of the missing angle and the number 9 is the adjacent or “right next to.” Hence, you are left with the Opposite side and the adjacent since the Hypotenuse is unused in this problem due to it being unlabeled. So 6 divided by 9 times the opposite of tangent which is Tan^-1 or on a basic calculator you would do the division first and then press the second key or secondary operations key. Then there will be a number in which shows you the exact angle in which you were missing.
Also learning the terms “SOH” “CAH” and “TOA” will help you exponentially when trying to find the equations to use. SOH: also known as Sine - is opposite over hypotenuse due to its alphabetical placement. Along with Cosine - adjacent over hypotenuse and Tangent which was the case of this triangle - opposite over adjacent.