To find \( mGHK \), we need to understand the relationship between the angles given the parallel lines \( GI \) and \( JL \).
Since \( GI \) and \( JL \) are parallel, angle \( LKH \) (which is given to be \( 134^\circ \)) and angle \( GHK \) are considered corresponding angles. Corresponding angles are equal when two parallel lines are cut by a transversal.
Therefore, we have:
\[ mGHK = mLKH = 134^\circ \]
So, \( mGHK \) is also \( 134^\circ \).