Question 465684
You have to use trigonometry to solve this problem. The angle you are trying to find is adjacent to the side with length 3, and is opposite the side with length 9. Therefore, you should use tangent, which is defined as opposite over adjacent. So, the equation is:
tan(x)=9/3
tan(x)=3
where 'x' is the number of degrees of angle B.
Now that we know that the tangent of angle B is 3, all we have to do is find the inverse tangent of three. The inverse tangent of 3 is approximately 71.565. This rounds to 72 degrees.