Answer:
4) Z and 43 deg. angle creates half-full angle, which is 180 deg., then you can subtract 43 from 180, to get z:
180 - 43 = z
z = 137 deg.
So z is 137 deg.
And after it 43 deg. and x, also creates a half-full angle, so again you have to subtract:
180 - 43 = x
X = 137 deg.
So x is 137.
Also x (137 deg.), and y creates half-full angle:
180 - 137 = y
Y = 43
Also there is much more easier way to do that:
There is rule, that in vertical angles (like in that situation), 2 angles are same, and rest 2 are also same. In this situation:
Z = X
43 = Y
And if you counted that is half-full angle, you get z is 137, and then x is also 137.
6) Vertical angles, like I said, have the same measure, so:
Angle 1 is also 105 deg.