This is dealing with an adjacent and hypotenuse variable, so you use cosine. Since your want to find the angle, u have to use cos^-1 times 5 over 9. Because when you use cosine its adjacent over hypotenuse. cos^-1(5/9)
You first have to figure out what you are going to use to find Angle B ( tanФ, cosФ or sinФ).
In this case you would use CosФ because you are given "adjescent over hypotenuse." Hence, 5/9.
Once you plug in CosФ=5/9 into your calculator you will get the angle of B. Which is: ∠B= 56.2510114°. Lastly, you would round this answer to the nearest hundredth.
Hope this helped! If you have any questions feel free to comment them.
