Answer: z=4
explanation: in order to find z you need to add all of the angles given together, and all triangles equal to 180 . so 8z+12^+19z+15z=180
42z+12=180
subtract 12 from 180 then your left with
42z=168
divide 42 on both sides
and you get 168/42 = 4
z=4
