Respuesta :

A= 4 because u divide 5 by 20.
Here, the figure is quadrilateral, we know in quadrilateral, opposite angles are equal, so 

20a + 30 = 17a + 48
20a - 17a = 48 - 30
3a = 18
a = 18/3
a = 6

In short, Your Answer would be 6

Hope this helps!