According this is a Right Triangle ( BCA = 90°) and the sum angles of a triangle is 180° :
90+5x+9x+6=180
14x=84
x=6
Then we have : ABC = 9(6)+6 =60
CBA = 5(6)=30
b :
Given that the size of the opposite angles to a vertex are equal and the sum of the interior angles of a triangle is 180 degrees, the size of all angles can be easily found.