Given
[tex]\tan(B)=\frac{15}{9}[/tex]
This is the same as
[tex]\tan(B)=\frac{5}{3}[/tex]
Take arctangent of both sides
[tex]B=arctan( \frac{5}{3})[/tex]
[tex]B=59.03624347[/tex]
Rounding to the nearest hundredth means round to two decimal places
[tex]B=59.04\degree[/tex]