we know that
If DF is parallel to GH
then
the measure of the angle EGH must be equal to 70° by corresponding angles
so
Find the measure of the angle EGH
In the triangle EGH
the sum of the internal angles must be equal to 180 degrees
42°+68°+∠EGH=180°
solve for ∠EGH
∠EGH=180-(42+68)
∠EGH=180-110
∠EGH=70°
therefore
The lines DF and GH are parallel
