Answer:
20, 120, 40
Explanation:
<G = 180 - (120+20) = 180 - 140 = 40°
And as the triangles are similar, their length may be different but the size of the angles will remain the same.
Do take note that triangle rotated and is now in a different position though.
So visually we can see that,
<X = <H = 20°
<Y = <I = 120°
<Z = <G = 40°