We have the following:
A.
To know the proportion of any type of class, we must divide the specific quantity of that class by the sum of all the classes.
As follows (music) :
[tex]\frac{40}{45+30+40+35}=\frac{40}{150}=\frac{4}{15}\rightarrow4\colon15[/tex]
B.
We know that a circle in total has 360 °, so to know the corresponding angle of music we must multiply that total by the proportion calculated previously
[tex]360\cdot\frac{4}{15}=96[/tex]
Therefore the corresponding angle is 96 degrees
